Larissa Nicholls

Identification of a novel genetic locus that is required for in vitro adhesion of a clinical isolate of enterohaemorrhagic Escherichia coli to epithelial cells.

Enterohaemorrhagic Escherichia coli (EHEC) are food‐borne intestinal pathogens with a low infectious dose. Adhesion of some EHEC strains to epithelial cells is attributed, in part, to intimin, but other factors may be required for the intestinal colonizing ability of these bacteria. In order to identify additional adherence factors of EHEC, we generated transposon mutants of a clinical EHEC isolate of serotype O111:H–, which displayed high levels of adherence to cultured Chinese hamster ovary (CHO) cells. One mutant was markedly deficient in CHO cell adherence, human red blood cell agglutination and autoaggregation. Sequence analysis of the gene disrupted in this mutant revealed a 9669 bp novel chromosomal open reading frame (ORF), which was designated efa1, for EHEC factor for adherence. efa1 displayed 28% amino acid identity with the predicted product of a recently described ORF from the haemolysin‐encoding plasmid of EHEC O157:H7. The amino termini of the putative products of these two genes exhibit up to 38% amino acid similarity to Clostridium difficile toxins A and B. efa1 occurred within a novel genetic locus, at least 15 kb in length, which featured a low G+C content, several insertion sequence homologues and a homologue of the Shigella flexneri enterotoxin ShET2. DNA probes prepared from different regions of efa1 hybridized with all of 116 strains of attaching–effacing E. coli (AEEC) of a variety of serotypes, including enteropathogenic E. coli (EPEC) and EHEC, but with none of 91 non‐AEEC strains. Nevertheless, efa1 was not required for the attachment–effacement phenotype, and the efa1 locus was not physically linked to the locus for enterocyte effacement (LEE) pathogenicity island, which is responsible for this phenotype in EPEC. These findings suggest that efa1 encodes a novel virulence‐associated determinant of AEEC, which contributes to the adhesive capacity of these bacteria.

Contribution of Efa1/LifA to the adherence of enteropathogenic Escherichia coli to epithelial cells

Enteropathogenic E. coli(EPEC) is an important diarrhoeal pathogen that induces characteristic lesions on the host intestine termed attaching and effacing (A/E) lesions. In this study we have examined the contribution of a large gene, efa1, which is present in all A/E pathogens, to the adherence phenotype of EPEC. An efa- derivative of EPEC JPN15 was constructed and this mutant was significantly less adherent to epithelial cells than the parent strain. The JPN15 efa- derivative was FAS-positive, produced EspA filaments and showed comparable levels of EspA secretion to JPN15. In addition, polyclonal antibodies raised to Efa1 partially inhibited the adherence of JPN15 to cultured epithelial cells. In further work, we showed that human and rabbit hosts infected with an A/E pathogen produced antibodies to Efa1 and we observed that the truncated form of efa1 present in EHEC O157:H7 was specific to that serotype. Generally efa1 was present in its entirety in the genomes of other A/E pathogens. Overall our data suggest that Efa1 has host cell binding activity, at least in tissue culture, and that it is produced during infection. These findings suggest that Efa1 may play a direct role in the pathogenesis of infections caused by A/E pathogens.

Curious energy consumers: Humans and nonhumans in assemblages of household practice

In international energy policy, programmes and consumer research, a dominant ideal consumer is emerging. This consumer is typically a human adult who has the agency to make autonomous, functional and rational decisions about his or her household’s energy consumption. This article seeks to disrupt this dominant anthropocentric conceptualisation of the consumer and provide new ways of knowing and potentially intervening in the lives of energy consumers. Drawing on qualitative research conducted with householders living in Sydney, Australia, and theories of practice, materiality and agency from sociology and science and technology studies, we seek to understand consumers as human and nonhuman actants operating in distributed assemblages of practice. We explore the implications of conceptualising non-traditional consumers of energy, such as babies, pets, pests and pool pumps, as performers of or materials in practices that consume energy. Our analysis provides new ways of potentially intervening in patterns of energy consumption. We argue that policy makers need to refocus their attention on finding routes into assemblages of practice to achieve change. We conclude by calling for further exploration and recognition of the myriad curious consumers found in households.

Understanding the Materiality of Neighbourhoods in ‘Healthy Practices’: Outdoor Exercise Practices in a New Master-planned Estate

Abstract The importance of neighbourhood design for health outcomes is well-established. Yet interactions between people and neighbourhood features, and how they are incorporated into daily routines, remain conceptually and empirically underdeveloped. Using theories of social practice this paper foregrounds the materiality of neighbourhoods to understand the role of natural and built features in everyday practices of physical activity. Drawing on longitudinal data about residents who recently moved to a master-planned estate, we discuss our findings in regard to the implications for those involved in designing and building new neighbourhoods. Our findings show how the presence—or absence—of certain material features affects the performance, frequency and timing of practices, such that they were modified, shifted to other (indoor) forms, or not performed at all. In addition, to effect change the meanings about, and skills to perform, exercise practices need to be supported in addition to their material elements. Lastly, the timing and synchronisation of exercise practices in relation to other daily routines is crucial to their ongoing performance. In focusing on how the material features of neighbourhoods co-constitute practices of outdoor physical activity we provide new insights into how design is implicated in health and wellbeing.

Planning for community: understanding diversity in resident experiences and expectations of social connections in a new urban fringe housing estate, Australia

ABSTRACT Master-planned estates are a major source of new housing for growing cities. Much research finds these residential developments lack genuine social connections between residents despite marketing of ‘close-knit’ community. Selandra Rise is a new residential development on the urban fringe of Melbourne, Australia. The estate was planned with a focus on community infrastructure and resident well-being. The resident population was younger and more culturally diverse than most other master-planned community case studies. A longitudinal research design was used to explore resident understanding, experiences and needs relating to place-based community. Interviews were conducted with residents before moving to the estate and 9–18 months after moving. Some residents considered community as an amenity provided by the master-planned environment that did not require their social participation. Others aspired to make social connections with neighbours but had varying levels of success. Past experiences which contributed to aspirations for connecting with local community, and the ways that these aims were realised or hindered, are discussed. Understanding diverse resident expectations of community and insights from their lived experience are used to make recommendations for planning new neighbourhoods and designing community development programmes.

Social Transit as Mass Transit in Australian Suburban Greenfield Development

The operation of public transport service in suburban developments, particularly new greenfield developments, can face considerable challenges. Suburban developments are often served primarily through bus transit, which struggles to balance a mass transit function against a social transit (e.g., local service) function. As a result, many suburban neighborhoods are served by infrequent, indirect services that appeal only to a captive transit ridership. This study explored the impact of a new bus service on a new development on the fringe of Melbourne, Australia: Selandra Rise in Clyde North. Three years after the development opened, a bus service was introduced to connect the development to the nearest town center and train station. Unlike many of the surrounding services, this bus service was deliberately planned to serve a mass transit function with direct, frequent service and relatively poor penetration into the suburb but high frequency. Two surveys were conducted to explore the use and the impact of the new bus service: a survey of Selandra Rise residents (including those who did not use the bus) and an on-bus survey of riders. The surveys showed that the bus serves a hybrid function as both mass transit and social transit. The implications of these findings for the planning of transit to new housing developments are discussed.

Exploring Hygge as a Desirable Design Vision for the Sustainable Smart Home

In this paper, we present an exploratory study of hygge as a low-energy design vision for the smart home. Hygge is a Danish concept that embodies aesthetic experiences related to conviviality, often shaped by orchestrating atmospheres through low-level lighting. To explore this vision, we probe two Australian households that already live with smart home lighting technology. We report on household reflections of embedding hygge into everyday life. We conclude by outlining future directions for exploring desirable and sus¬tainable smart home visions.