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BACKGROUND: Phytohormones are small molecules that regulate virtually every aspect of plant growth and development, from basic cellular processes, such as cell expansion and division, to whole plant environmental responses. While the phytohormone levels and distribution thus tell the plant how to adjust itself, the corresponding growth alterations are actuated by cell wall modification/synthesis and internal turgor. Plant cell walls are complex polysaccharide-rich extracellular matrixes that surround all plant cells. Among the cell wall components, cellulose is typically the major polysaccharide, and is the load-bearing structure of the walls. Hence, the cell wall distribution of cellulose, which is synthesized by large Cellulose Synthase protein complexes at the cell surface, directs plant growth. SCOPE: Here, we review the relationships between key phytohormone classes and cellulose deposition in plant systems. We present the core signalling pathways associated with each phytohormone and discuss the current understanding of how these signalling pathways impact cellulose biosynthesis with a particular focus on transcriptional and post-translational regulation. Because cortical microtubules underlying the plasma membrane significantly impact the trajectories of Cellulose Synthase Complexes, we also discuss the current understanding of how phytohormone signalling impacts the cortical microtubule array. CONCLUSION: Given the importance of cellulose deposition and phytohormone signalling in plant growth and development, one would expect that there is substantial cross-talk between these processes; however, mechanisms for many of these relationships remain unclear and should be considered as the target of future studies.

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Modern metabolomic approaches that generate more comprehensive phytochemical profiles than were previously available are providing new opportunities for understanding plant-animal interactions. Specifically, we can characterize the phytochemical landscape by asking how a larger number of individual compounds affect herbivores and how compounds covary among plants. Here we use the recent colonization of alfalfa (Medicago sativa) by the Melissa blue butterfly (Lycaeides melissa) to investigate the effects of indivdiual compounds and suites of covarying phytochemicals on caterpillar performance. We find that survival, development time, and adult weight are all associated with variation in nutrition and toxicity, including biomolecules associated with plant cell function as well as putative anti-herbivore action. The plant-insect interface is complex, with clusters of covarying compounds in many cases encompassing divergent effects on different aspects of caterpillar performance. Individual compounds with the strongest associations are largely specialized metabolites, including alkaloids, phenolic glycosides, and saponins. The saponins are represented in our data by more than 25 individual compounds with beneficial and detrimental effects on L. melissa caterpillars, which highlights the value of metabolomic data as opposed to approaches that rely on total concentrations within broad defensive classes.

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A randomised controlled trial evaluated the Aussie Optimism Program in preventing anxiety and depression. Grade 7 students (n = 496) from disadvantaged government schools in Perth Western Australia, participated. Six schools were randomly assigned to Aussie Optimism and six schools received their usual health education lessons. Students completed questionnaires on depression, anxiety, attribution style, and social skills. Parents completed the Child Behavior Checklist. No significant group effects were found for student-reported data. Parents of intervention group only students reported reductions in internalizing problems at post-test. No follow-up group effects were significant. Students and teachers found the program acceptable.

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A controlled trial was conducted to evaluate a prevention program aimed at reducing depressive and anxious symptoms in rural school children. Seventh-grade children with elevated depression were selected. Nine primary schools (n = 90) were randomly assigned to receive the program, and 9 control schools (n = 99) received their usual health education classes. Children completed questionnaires on depression, anxiety, explanatory style, and social skills. Parents completed the Child Behavior Checklist (T. M. Achenbach, 1991). No intervention effects were found for depression. Intervention group children reported less anxiety than the control group after the program and at 6-month follow-up and more optimistic explanations at postintervention. Intervention group parents reported fewer child internalizing and externalizing symptoms at postintervention only.

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This paper is written on behalf of the West Australian Branch of the Australasian Faculty of Public Health Medicine. As public health physicians, we feel it is important that public health professionals should contribute constructively to address the needs of a socially deprived, marginalised group with high rates of physical and psychiatric morbidity. Depending on the definition, there are between 18 and 48 million asylum seekers and refugees in the world. Most seek protection in neighbouring countries, largely in Africa and Asia, rather than coming to North America, Europe and Australasia. Contrary to popular belief, numbers of successful applications to Australia's humanitarian program have actually fallen. This article attempts to correct misperceptions and misapprehensions about the effect of asylum seekers on the public health. Public health professionals should lobby for changes to Govemment policy that at present leave asylum seekers vulnerable to a cycle of poverty, ill-health and limited access to health services.

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