Search

Abstract: Six active methane seeps and one cold-water reef that may represent a relict seep were mapped at Omakere Ridge on New Zealand''s Hikurangi Margin during cruises SO191 and TAN0616. Hydroacoustic flares, interpreted to be bubbles of methane rising through the water column were identified in the area. The seep sites and the cold-water reef were characterised by regions of high backscatter intensity on sidescan sonar records, or moderate backscatter intensity where the seep was located directly below the path of the sidescan towfish. The majority of sites appear as elevated features (2–4 m) in multibeam swath data. Gas blanking and acoustic turbidity were observed in sub-bottom profiles through the sites. A seismic section across two of the sites (Bear''s Paw and LM-9) shows a BSR suggesting the presence of gas hydrate as well as spots of high amplitudes underneath and above the BSR indicating free gas. All sites were ground truthed with underwater video observations, which showed the acoustic features to represent authigenic carbonate rock structures. Live chemosynthetic biotic assemblages, including siboglinid tube worms, vesicomyid clams, bathymodiolin mussels, and bacterial mats, were observed at the seeps. Cold-water corals were the most conspicuous biota of the cold-water reef but widespread vesicomyid clam shells indicated past seep activity at all sites. The correlation between strong backscatter features in sidescan sonar images and seep-related seabed features is a powerful tool for seep exploration, but differentiating the acoustic features as either modern or relict seeps requires judicial analysis and is most effective when supported by visual observations. [Copyright &y& Elsevier]

A seismic structure imaged in a single 2D seismic profile from the offshore Canning Basin, Western Australia, is interpreted to be a possible complex impact crater on the basis of its seismic character. The feature, herein referred to as the Haines Structure, is symmetrical in two dimensions over ∼2.5 km and comprises a centrally uplifted basal surface, a depressed upper surface, a highly deformed intervening package and an overlying horizon that is 'sagging' over the depression. The possible impact structure lies within carbonate units of Eocene or Early Oligocene age as determined from seismic correlation to petroleum exploration wells. The structure has not been drilled; therefore distinguishing characteristics used to define an impact origin, such as shock metamorphism, are not available. Comparison with other features in the Neogene succession of Australia's North West Shelf that have previously been interpreted as impact structures highlights the presence of key elements in the Haines Structure that characterise known complex impact craters, and the absence of seismic features related to alternative processes, such as a link to deeper structures that would be expected beneath a volcanic pipe. [ABSTRACT FROM AUTHOR]

A suite of tool marks were observed in the seaward section of a small estuary on the south coast of New South Wales. The marks were formed through wind-generated waves dragging Eucalyptus leaves and Casuarina fronds over the backshore sands that separate the closed estuary from the sea. Some of the marks formed through the process of tilting, which has not previously been recognised in an Australian setting. A number of the more complex marks closely resemble trace fossils left by fish, and differentiation between the two in the sedimentary record could be difficult. If correctly identified as tool marks, then they could give a spurious estimate of palaeoflow direction, as they correspond to the orientation of the prevailing winds at the time of formation. This study highlights the need for judicious interpretation of ambiguous grooves in the sedimentary record. [ABSTRACT FROM AUTHOR]

The case history of a patient admitted to the ICU with interstitial lung disease deteriorating to respiratory failure is presented. Problems in distinguishing between infection and disease progression are discussed and the role of transplantation in ventilated patients is examined. [ABSTRACT FROM AUTHOR]

Summary: 1.Grants for wildlife enhancement in the British Isles have supported the widespread planting of new hedges along field margins. However, much of the planted material, particularly of hawthorn Crataegus monogyna, has been obtained from the continental mainland of Europe. There is a need to assess the implications of this practice for hedgerow performance and for the conservation of indigenous genetic variation. 2.One local ecotype and eight commercial provenances (four British and four continental European) of hawthorn were planted in an experimental hedge at both an exposed upland site and a sheltered lowland site. Sections of hedge were planted with or without fencing and with or without mulching in all combinations. Growth and thorniness were assessed over 3 years, and phenology and disease over 2 years. 3.At both sites, the most locally obtained provenance had the latest bud-burst, exhibited the least severe symptoms of mildew and was the most thorny. It also showed the greatest height increment at the upland site, but was relatively slow-growing at the lowland site. 4.An imported Hungarian provenance had early bud-burst, showed a high growth rate and suffered the most severe mildew. A commercially obtained British native provenance was aberrant in its extremely early bud-burst and other attributes comparable with the Hungarian provenance, indicating the possibility of misidentification at some stage of production or supply. 5.In the absence of fencing, at the upland site hawthorn mortality was 100% compared with only 3% at the lowland site. In fenced plots there was c. 320% greater growth when mulching was used. 6.The results suggest that for greater establishment success and hence cost benefits in hedge planting, as well as for greater environmental benefits, there should be closer matching of hawthorn provenance to the planting site. The use of commercial material has demonstrated that locally provenanced material can be superior to any com... [ABSTRACT FROM AUTHOR]

Abstract Deficits in social memory, cognition, and aberrant responses to stimulants are common among persons affected by schizophrenia and other conditions with a presumed developmental etiology. We previously found that expression changes in the adenosine metabolizing enzyme adenosine kinase (ADK) in the adult brain are associated with deficits in various cognitive domains. To distinguish between developmental and adult functions of ADK, we used two transgenic mouse lines with widespread disruption of ADK expression in the adult brain, but differences in the onset of ADK deletion. Specifically, we compared Nestin-Cre+/-:ADK-floxfl/fl (ADKΔBrain) mice with global loss of ADK in the whole brain, beginning in mid-gestation and persisting for life, with Gfa2-Cre+/-:ADK-floxfl/fl (ADKΔAstro) mice that have normal ADK expression throughout development, but lose astrocyte-specific ADK-expression in young adulthood. Because ADK-expression in adulthood is generally confined to astrocytes, adult ADKΔAstro mice show a similar expression profile of ADK in key areas of the brain related to neuropsychiatric behavior, compared to adult ADKΔBrain mice. We sought to determine a neurodevelopmental role of ADK on the expression of psychiatric behaviors in adult male and female mice. Adult ADKΔBrain mice showed significant deficits in social memory in males, significant contextual learning impairments in both sexes, and a hyper-responsiveness to amphetamine in males. In contrast, ADKΔAstro mice showed normal social memory and contextual learning but hypo-responsiveness to amphetamine in males. Our results demonstrate a key developmental role of ADK in mediating behaviors in adulthood related to neuropsychiatric disease and support the greater prevalence of these disorders among males. Highlights • Perturbation of adenosine kinase expression during development results in behavioral deficits, predominately in male mice. • There were prominent sex differences in behavior, in line with clinical populations, in adenosine kinase deficient mice. • Adenosine homeostasis may play a role during development in determining susceptibility to later neuropsychiatric disease. [ABSTRACT FROM AUTHOR]

Examines the identification of Cecidophyopsis mites based on sequence repeats of ribosomal DNA internal transcribed spacer-1 sequences. Use of polymerase chain reaction (PCR); Description of the mites; Assessment on the genetic variability of mites.

For cell penetrating peptides (CPPs) to fulfil their promise as effective delivery vectors we need a better understanding of their mechanisms of cell binding and uptake. This is especially the case when they are linked to different types of cargo. Here we describe new studies based on our previous findings suggesting that, for peptide-CPP chimeras, distal hydrophobic residues upstream of the CPP sequence can have profound effects on the way they interact with cells. We studied peptides bearing an N-terminal Glycine or Phenylalanine linked via a neutral and flexible bridging group, SGSGSGSG, to three well-studied CPPs: octaarginine, penetratin and TP10. Using a combination of flow cytometry, live-cell imaging and image analysis we examined the effects of this single amino acid change on binding and uptake of Alexa488-fluorophore, bovine serum albumin and quantum dot cargoes. The influence of the glycine–phenylalanine switch for fluorophore delivery was most dramatic in TP10, increasing cellular uptake by 4.4 and 9.9 fold in non-adherent and adherent cells, respectively. Only penetratin showed effective uptake of bovine serum albumin with the phenylalanine variant showing an increase of 1.6 fold over the glycine variant. The uptake of quantum dots was most efficiently demonstrated by octaarginine, with the glycine variant increasing uptake 4.8 fold and the phenylalanine variant increasing uptake 9.5 fold over quantum dots alone. Overall the data demonstrate that hydrophobicity distal to the CPP could be utilised to enhance their capacity to bind to the cell membrane and deliver a range of macromolecules to the insides of cells. [ABSTRACT FROM AUTHOR]

Abstract: Cell penetrating peptides (CPPs) have been extensively studied as vectors for cellular delivery of therapeutic macromolecules. It is widely accepted that they can enter cells directly across the plasma membrane but also gain access through endocytic pathways that are yet to be fully defined. Here we developed siRNA methods in epithelial cell lines, HeLa and A431, to inhibit endocytic pathways regulated by clathrin heavy chain, flotillin-1, caveolin-1, dynamin-2 and Pak-1. In each case, functional uptake assays were developed to characterize the requirement for these proteins, and the pathways they regulate, in the internalisation of defined endocytic probes and also the CPPs octaarginine and HIV-Tat. Peptide uptake was only inhibited in A431 cells depleted of the macropinocytosis regulator Pak-1, but experimental variables including choice of cell line, pharmacological inhibitor, macropinocytic probe and serum starvation significantly influence our ability to assess and assign this pathway as an important route for CPP uptake. Actin disruption with Cytochalasin D inhibited peptide entry in both cell lines but the effects of this agent on dextran uptake was cell line dependent, reducing uptake in HeLa cells and increasing uptake in A431 cells. This was further supported in experiments inducing actin stabilisation by Jasplakinolide, emphasising that the actin cytoskeleton can both promote and hinder endocytosis. Overall the data identify important aspects regarding the comparative mechanisms of CPP uptake and macropinocytosis, and accentuate the significant methodological challenges of studying this pathway as an endocytic portal and an entry route for drug delivery vectors. [Copyright &y& Elsevier]

Abstract: A variety of shallow gas indicators and fluid migration pathways have been interpreted from new sub-bottom profiler, multibeam bathymetry, side-scan sonar, and echo-sounder data together with geochemical analyses of sampled sediments from the northern Arafura Sea, offshore Northern Australia. This study provides new geological data and a seismic stratigraphy of the youngest units in the Money Shoal Basin, in an area that has not been closely studied in over 30 years. The shallow gas indicators include pockmarks, low frequency enhanced reflectors and acoustic blanking. These indicators are supported by gas within shallow cores. Geochemistry indicates that this gas has a microbial origin but deeper fluid movement is also suggested by the presence of interpreted hydrocarbon slicks based on synthetic aperture radar data. A region of likely hydrocarbon seepage is indicated by the clear coincidence of shallow gas indicators with an area of increased faulting and a zone of poor quality seismic data (recognised on conventional seismic data), together with anomalies (interpreted on remote-sensing data) aligned with mapped deep structures. [Copyright &y& Elsevier]

Abstract: For the first time in Australia, active present-day hydrocarbon seepage has been imaged—on the tropical carbonate Yampi Shelf, in 50 and 90m water depth. Seepage is evidenced by gas plumes in the water column that are associated with seabed features, such as clusters of reflective blocks, hard-grounds, pockmark fields, and mounds. Seepage activity and intensity seems to vary with changes in pressure related to macro-tidal cycles. The seabed features coincide with sub-surface features such as areas of seismic signal attenuation under high amplitude reflectors, seismic discontinuities and bright spots. Hydrocarbon migration-seepage pathways appear to be controlled by the reactivation of pre-existing fractures and dykes within the basement. The types of seabed features and their preservation on a tropical carbonate shelf are strongly influenced by the coarse bioclastic nature of sediments and the high energy of macro-tidal currents and storm reworking. [Copyright &y& Elsevier]