The antigen 43 structure reveals a molecular velcro-like mechanism of autotransporter-mediated bacterial clumping

Aggregation and biofilm formation are critical mechanisms for bacterial resistance to host immune factors and antibiotics. Autotransporter (AT) proteins, which represent the largest group of outer-membrane and secreted proteins in Gram-negative bacteria, contribute significantly to these phenotypes. Despite their abundance and role in bacterial pathogenesis, most AT proteins have not been structurally characterized, and there is a paucity of detailed information with regard to their mode of action. Here we report the structure–function relationships of Antigen 43 (Ag43a), a prototypic self-associating AT protein from uropathogenic Escherichia coli. The functional domain of Ag43a displays a twisted L-shaped β-helical structure firmly stabilized by a 3D hydrogen-bonded scaffold. Notably, the distinctive Ag43a L shape facilitates self-association and cell aggregation. Combining all our data, we define a molecular “Velcro-like” mechanism of AT-mediated bacterial clumping, which can be tailored to fit different bacterial lifestyles such as the formation of biofilms.

Structure and function of DsbA, a key bacterial oxidative folding catalyst

Since its discovery in 1991, the bacterial periplasmic oxidative folding catalyst DsbA has been the focus of intense research. Early studies addressed why it is so oxidizing and how it is maintained in its less stable oxidized state. The crystal structure of Escherichia coli DsbA (EcDsbA) revealed that the oxidizing periplasmic enzyme is a distant evolutionary cousin of the reducing cytoplasmic enzyme thioredoxin. Recent significant developments have deepened our understanding of DsbA function, mechanism, and interactions: the structure of the partner membrane protein EcDsbB, including its complex with EcDsbA, proved a landmark in the field. Studies of DsbA machineries from bacteria other than E. coli K-12 have highlighted dramatic differences from the model organism, including a striking divergence in redox parameters and surface features. Several DsbA structures have provided the first clues to its interaction with substrates, and finally, evidence for a central role of DsbA in bacterial virulence has been demonstrated in a range of organisms. Here, we review current knowledge on DsbA, a bacterial periplasmic protein that introduces disulfide bonds into diverse substrate proteins and which may one day be the target of a new class of anti-virulence drugs to treat bacterial infection. Antioxid. Redox Signal. 14, 1729–1760.

Behaviour v structure : Tribunal’s AGL Energy merger authorisation

Section 95AT of the Competition and Consumer Act 2010 (Cth) (CCA) provides that the Tribunal may grant an authorisation to acquire shares or assets that would otherwise contravene s 50. Section 95AT was inserted by the Trade Practices Legislation Amendment Act 2006 (Cth) and commenced on 1 January 2007. In Application for Authorisation of Macquarie Generation by AGL Energy Limited, (AGL Energy) the Tribunal has for the first time granted AGL Energy Limited (AGL) a conditional authorisation to acquire the assets of Macquarie Generation from the NSW Government.

Vibrational spectroscopy of the borate mineral priceite : implications for the molecular structure

Priceite is a calcium borate mineral and occurs as white crystals in the monoclinic pyramidal crystal system. We have used a combination of Raman spectroscopy with complimentary infrared spectroscopy and scanning electron microscopy with Energy-dispersive X-ray Spectroscopy (EDS) to study the mineral priceite. Chemical analysis shows a pure phase consisting of B and Ca only. Raman bands at 956, 974, 991, and 1019 cm−1 are assigned to the BO stretching vibration of the B10O19 units. Raman bands at 1071, 1100, 1127, 1169, and 1211 cm−1 are attributed to the BOH in-plane bending modes. The intense infrared band at 805 cm−1 is assigned to the trigonal borate stretching modes. The Raman band at 674 cm−1 together with bands at 689, 697, 736, and 602 cm−1 are assigned to the trigonal and tetrahedral borate bending modes. Raman spectroscopy in the hydroxyl stretching region shows a series of bands with intense Raman band at 3555 cm−1 with a distinct shoulder at 3568 cm−1. Other bands in this spectral region are found at 3221, 3385, 3404, 3496, and 3510 cm−1. All of these bands are assigned to water stretching vibrations. The observation of multiple bands supports the concept of water being in different molecular environments in the structure of priceite. The molecular structure of a natural priceite has been assessed using vibrational spectroscopy.

Functional magnetic resonance brain imaging of executive cognitive performance in young first-episode schizophrenia patients and age-matched long-term cannabis users

Converging evidence from epidemiological, clinical and neuropsychological research suggests a link between cannabis use and increased risk of psychosis. Long-term cannabis use has also been related to deficit-like “negative” symptoms and cognitive impairment that resemble some of the clinical and cognitive features of schizophrenia. The current functional brain imaging study investigated the impact of a history of heavy cannabis use on impaired executive function in first-episode schizophrenia patients. Whilst performing the Tower of London task in a magnetic resonance imaging scanner, event-related blood oxygenation level-dependent (BOLD) brain activation was compared between four age and gender-matched groups: 12 first-episode schizophrenia patients; 17 long-term cannabis users; seven cannabis using first-episode schizophrenia patients; and 17 healthy control subjects. BOLD activation was assessed as a function of increasing task difficulty within and between groups as well as the main effects of cannabis use and the diagnosis of schizophrenia. Cannabis users and non-drug using first-episode schizophrenia patients exhibited equivalently reduced dorsolateral prefrontal activation in response to task difficulty. A trend towards additional prefrontal and left superior parietal cortical activation deficits was observed in cannabis-using first-episode schizophrenia patients while a history of cannabis use accounted for increased activation in the visual cortex. Cannabis users and schizophrenia patients fail to adequately activate the dorsolateral prefrontal cortex, thus pointing to a common working memory impairment which is particularly evident in cannabis-using first-episode schizophrenia patients. A history of heavy cannabis use, on the other hand, accounted for increased primary visual processing, suggesting compensatory imagery processing of the task.

Family structure and change through middle childhood : the impact on children's adjustment and achievement

This research project investigated the influence of family transitions on children's adjustment and school achievement across the primary school years, in single-parent, re-partnered and two-parent families. The quality of children's relationships with parents, teachers and peers were predictive of more positive outcomes, regardless of family structure. The research analysed data from the Kindergarten Cohort participating in Growing Up in Australia: The Longitudinal Study of Australian Children. Across the age span of the children studied, cumulative effects of any residential or school changes, or decreased family income, associated with family transitions, were more likely to predict poorer child outcomes in behaviour adjustment and school achievement.

Design after design to bridge between people living with cognitive or sensory impairments, their friends and proxies

A carer or teacher often plays the role of proxy or spokesperson for a person living with an intellectual disability or form of cognitive or sensory impairment. Our research undertook co-design with people living with cognitive and sensory impairments and their proxies in order to explore new ways of facilitating communication. We developed simple functioning interactive prototypes to support people with a diverse range of competencies to communicate and explore their use. Deployment of the prototypes enabled use, appropriation and design after design by our two participant groups; adults living with cognitive or sensory impairments and children identified with language delays and autism spectrum disorder. The prototypes supported concrete expression of likes, dislikes, capabilities, emotional wants and needs and forms of expression that hitherto had not been fostered, further informing design. Carers and designers were surprised at the ways in which the technology was used and how it fostered new forms of social interaction and expression. We elaborate on how design after design can be an effective approach for engaging people living with intellectual disabilities, giving them greater capacity for expression and power in design and offering the potential to expand and deepen their social relationships.

Structure and palaeoenvironmental implications of inter-branch coenosteum-rich skeleton in corymbose Acropora species

Coral reefs provide an increasingly important archive of palaeoclimate data that can be used to constrain climate model simulations. Reconstructing past environmental conditions may also provide insights into the potential of reef systems to survive changes in the Earth’s climate. Reef-based palaeoclimate reconstructions are predominately derived from colonies of massive Porites, with the most abundant genus in the Indo-Pacific—Acropora—receiving little attention owing to their branching growth trajectories, high extension rates and secondary skeletal thickening. However, inter-branch skeleton (consisting of both coenosteum and corallites) near the bases of corymbose Acropora colonies holds significant potential as a climate archive. This region of Acropora skeleton is atypical, having simple growth trajectories with parallel corallites, approximately horizontal density banding, low apparent extension rates and a simple microstructure with limited secondary thickening. Hence, inter-branch skeleton in Acropora bears more similarities to the coralla of massive corals, such as Porites, than to traditional Acropora branches. Cyclic patterns of Sr/Ca ratios in this structure suggest that the observed density banding is annual in nature, thus opening up the potential to use abundant corymbose Acropora for palaeoclimate reconstruction.

Exploring cognitive style and task-specific preferences for process representations

Process models describe someone’s understanding of processes. Processes can be described using unstructured, semi-formal or diagrammatic representation forms. These representations are used in a variety of task settings, ranging from understanding processes to executing or improving processes, with the implicit assumption that the chosen representation form will be appropriate for all task settings. We explore the validity of this assumption by examining empirically the preference for different process representation forms depending on the task setting and cognitive style of the user. Based on data collected from 120 business school students, we show that preferences for process representation formats vary dependent on application purpose and cognitive styles of the participants. However, users consistently prefer diagrams over other representation formats. Our research informs a broader research agenda on task-specific applications of process modeling. We offer several recommendations for further research in this area.

Spatially varying ground motion effects on seismic response of adjacent structures considering soil-structure interaction

Spatial variation of seismic ground motions is caused by incoherence effect, wave passage, and local site conditions. This study focuses on the effects of spatial variation of earthquake ground motion on the responses of adjacent reinforced concrete (RC) frame structures. The adjacent buildings are modeled considering soil-structure interaction (SSI) so that the buildings can be interacted with each other under uniform and non-uniform ground motions. Three different site classes are used to model the soil layers of SSI system. Based on fast Fourier transformation (FFT), spatially correlated non-uniform ground motions are generated compatible with known power spectrum density function (PSDF) at different locations. Numerical analyses are carried out to investigate the displacement responses and the absolute maximum base shear forces of adjacent structures subjected to spatially varying ground motions. The results are presented in terms of related parameters affecting the structural response using three different types of soil site classes. The responses of adjacent structures have changed remarkably due to spatial variation of ground motions. The effect can be significant on rock site rather than clay site.

The potential for new understandings of normal and abnormal cognition by integration of neuroimaging and behavioral data : Not an exercise in carrying coals to Newcastle

Discovering the means to prevent and cure schizophrenia is a vision that motivates many scientists. But in order to achieve this goal, we need to understand its neurobiological basis. The emergent metadiscipline of cognitive neuroscience fields an impressive array of tools that can be marshaled towards achieving this goal, including powerful new methods of imaging the brain (both structural and functional) as well as assessments of perceptual and cognitive capacities based on psychophysical procedures, experimental tasks and models developed by cognitive science. We believe that the integration of data from this array of tools offers the greatest possibilities and potential for advancing understanding of the neural basis of not only normal cognition but also the cognitive impairments that are fundamental to schizophrenia. Since sufficient expertise in the application of these tools and methods rarely reside in a single individual, or even a single laboratory, collaboration is a key element in this endeavor. Here, we review some of the products of our integrative efforts in collaboration with our colleagues on the East Coast of Australia and Pacific Rim. This research focuses on the neural basis of executive function deficits and impairments in early auditory processing in patients using various combinations of performance indices (from perceptual and cognitive paradigms), ERPs, fMRI and sMRI. In each case, integration of two or more sources of information provides more information than any one source alone by revealing new insights into structure-function relationships. Furthermore, the addition of other imaging methodologies (such as DTI) and approaches (such as computational models of cognition) offers new horizons in human brain imaging research and in understanding human behavior.

Telecommunications Impacts on the Structure and Organisation of Male Sex Work

(Sub)Urban Sexscapes brings together a collection of theoretically-informed and empirically rich case studies highlighting the contemporary and historical geographies and regulation of the commercial sex industry. Contributions in this edited volume examine the spatial and regulatory contours of the sex industry from a range of disciplinary perspectives—urban planning, urban geography, urban sociology, and, cultural and media studies—and geographical contexts—Australia, the UK, US and North Africa. In overall terms, (Sub)urban Sexscapes highlights the mainstreaming of commercial sex premises—sex shops, brothels, strip clubs and queer spaces—and products—sex toys, erotic literature and pornography—now being commonplace in night time economy spaces, the high street, suburban shopping centres and the home. In addition, the aesthetics of commercial and alternative sexual practices—BDSM and pornography—permeate the (sub)urban landscape via billboards, newspapers and magazines, television, music videos and the Internet. The role of sex, sexuality and commercialized sex, in contributing to the general character of our cities cannot be ignored. In short, there is a need for policy-makers to be realistic about the historical, contemporary and future presence of the sex industry. Ultimately, the regulation of the sex industry should be informed by evidence as opposed to moral panics.

Can’t we all just get along? A qualitative investigation of the cognitive processes motivating driver aggression.

Although driver aggression has been identified as contributing to crashes, current understanding of the fundamental causes of the behaviour is poor. Two key reasons for this are evident. Firstly, existing research has been largely atheoretical, with no unifying conceptual framework guiding investigation. Secondly, emphasis on observable behaviours has resulted in limited knowledge of the underlying thought processes that motivate behaviour. Since driving is fundamentally a social situation, requiring drivers to interpret on-road events, insight regarding these perception and appraisal processes is paramount in advancing understanding of the underlying causes. Thus, the current study aimed to explore the cognitive appraisal processes involved in driver aggression, using a conceptual model founded on the General Aggression Model (Anderson & Bushman, 2002). The present results reflect the first of several studies testing this model. Participants completed 3 structured driving diaries to explore perceptions and cognitions. Thematic analysis of diaries identified several cognitive themes. The first, ‘driving etiquette’ concerned an implied code of awareness and consideration for other motorists, breaches of which were strongly associated with reports of anger and frustration. Such breaches were considered intentional; attributed to dispositional traits of another driver, and precipitated the second theme, ‘justified retaliation’. This theme showed that drivers view their aggressive behaviour as warranted, to convey criticism towards another motorist’s etiquette violation. However, the third theme, ‘superiority’ suggested that those refraining from an aggressive response were motivated by a desire to perceive themselves as ‘better’ than the offending motorists. Collectively, the themes indicate deep-seated and complex thought patterns underlying driver aggression, and suggest the behaviour will be challenging to modify. Implications of these themes in relation to the proposed model will be discussed, and continued research will explore these cognitive processes further, to examine their interaction with person-related factors.

Comparison of intraspecific genetic structure among related chironomids (Diptera) from New Zealand and Patagonia : disparity between potential and realized dispersal

Population genetic studies of freshwater invertebrate taxa in New Zealand and South America are currently few despite the geologically and climatically dynamic histories of these regions. The focus of our study was a comparison of the influence on realized dispersal of 2 closely related nonbiting midges (Chironomidae) of population fragmentation on these separated austral land masses. We used a 734-base pair (bp) fragment of cytochrome c oxidase subunit I (COI) to investigate intraspecific genetic structure in Naonella forsythi Boothroyd in New Zealand and Ferringtonia patagonica Edwards in Patagonia. We proposed hypotheses about their potential dispersal and, hence, expected patterns of genetic structure in these 2 species based on published patterns for the closely related Australian taxon Echinocladius martini Cranston. Genetic structure revealed for both N. forsythi and F. patagonica was characterized by several highly divergent (2.0–10.5%) lineages of late Miocene–Pliocene age within each taxon that were not geographically localized. Many were distributed widely. This pattern differed greatly from population structure in E. martini, which was typified by much greater endemicity of divergent genetic lineages. Nevertheless, diversification of lineages in all 3 taxa appeared to be temporally congruent with the onset of late Miocene glaciations in the southern hemisphere that may have driven fragmentation of suitable habitat, promoting isolation of populations and divergence in allopatry. We argue that differences in realized dispersal post-isolation may be the result of differing availability of suitable habitat in interglacial periods.