Constitutive and facultative crassulacean acid metabolism (CAM) in Cuban oregano, Coleus amboinicus (Lamiaceae)

© 2020 CSIRO. Plants exhibiting the water-conserving crassulacean acid metabolism (CAM) photosynthetic pathway provide some of the most intriguing examples of photosynthetic diversity and plasticity. Here, a largely unnoticed facet of CAM-plant photosynthesis is highlighted: the co-occurrence of ontogenetically controlled constitutive and environmentally controlled facultative CAM in a species. Both forms of CAM are displayed in leaves of Coleus amboinicus Lour. (Lamiaceae), a semi-succulent perennial plant with oregano-like flavour that is native to southern and eastern Africa and naturalised elsewhere in the tropics. Under well-watered conditions, leaves assimilate CO2 predominantly by the C3 pathway. They also display low levels of CO2 uptake at night accompanied by small nocturnal increases in leaf tissue acidity. This indicates the presence of weakly expressed constitutive CAM. CAM expression is strongly enhanced in response to drought stress. The drought-enhanced component of CAM is reversible upon rewatering and thus considered to be facultative. In contrast to C. amboinicus, the thin-leaved closely related Coleus scutellarioides (L.) Benth. exhibits net CO2 fixation solely in the light via the C3 pathway, both under well-watered and drought conditions. However, low levels of nocturnal acidification detected in leaves and stems indicate that the CAM cycle is present. The highly speciose mint family, which contains few known CAM-exhibiting species and is composed predominantly of C3 species, appears to be an excellent group of plants for studying the evolutionary origins of CAM and for determining the position of facultative CAM along the C3-full CAM trajectory

Splash!: a prospective birth cohort study of the impact of environmental, social and family-level influences on child oral health and obesity related risk factors and outcomes

Background: Dental caries (decay) is the most prevalent disease of childhood. It is often left untreated and can impact negatively on general health, and physical, developmental, social and learning outcomes. Similar to other health issues, the greatest burden of dental caries is seen in those of low socio-economic position. In addition, a number of diet-related risk factors for dental caries are shared risk factors for the development of childhood obesity. These include high and frequent consumption of refined carbohydrates (predominately sugars), and soft drinks and other sweetened beverages, and low intake of (fluoridated) water. The prevalence of childhood obesity is also at a concerning level in most countries and there is an opportunity to determine interventions for addressing both of these largely preventable conditions through sustainable and equitable solutions. This study aims to prospectively examine the impact of drink choices on child obesity risk and oral health status.Methods/Design: This is a two-stage study using a mixed methods research approach. The first stage involves qualitative interviews of a sub-sample of recruited parents to develop an understanding of the processes involved in drink choice, and inform the development of the Discrete Choice Experiment analysis and the measurement instruments to be used in the second stage. The second stage involves the establishment of a prospective birth cohort of 500 children from disadvantaged communities in rural and regional Victoria, Australia (with and without water fluoridation). This longitudinal design allows measurement of changes in the child&rsquo;s diet over time, exposure to fluoride sources including water, dental caries progression, and the risk of childhood obesity.Discussion: This research will provide a unique contribution to integrated health, education and social policy and program directions, by providing clearer policy relevant evidence on strategies to counter social and environmental factors which predispose infants and children to poor health, wellbeing and social outcomes; and evidence-based strategies to promote health and prevent disease through the adoption of healthier lifestyles and diet. Further, given the absence of evidence on the processes and effectiveness of contemporary policy implementation, such as community water fluoridation in rural and regional communities it&rsquo;s approach and findings will be extremelyinformative.<br /

Choosing foods for infants: A qualitative study of the factors that influence mothers

Background Examining the experiences of parents making food choices for infants is important because ultimately this influences what infants eat. Infancy is a critical period when food preferences and eating behaviour begin to develop, shaping dietary patterns, growth and health outcomes. There is limited evidence regarding what or why foods are chosen for infants. Objective To describe the experiences of mothers making food choices for their infant children. Methods Semi‐structured interviews with 32 Australian mothers of infants aged four to 15 months from a range of socioeconomic backgrounds. An inductive thematic analysis through a process of constant comparison was conducted on transcribed interviews. Results Mothers described many ideas and circumstances which influenced food choices they made for infants. Themes were developed which encapsulate how the wider environment and individual circumstances combine to result in the food choices made for infants. Beliefs, values, norms and knowledge were a central influence on choices. Cost, quality and availabilities of various foods were also key factors. Related to this, and combined with inherent factors such as perishability and infant acceptability, fresh fruits and vegetables were often singled out as an easy or difficult choice. Influences of time, parents' capacities, social connections and different information sources were clearly apparent. Finally infants' own preferences and how parents helped infants with learning to eat were also key influences on food choices. Conclusions Choosing foods for infants is a complex social practice. An ecological framework depicting the multiple influences on what people eat and sociological theory on food choice regarding the role of ‘social structure’ and ‘human agency’ are both applicable to the process of choosing foods for infants. Equity issues may be key regarding the degree to which mothers can choose particular foods for infants (e.g. choosing foods which promote health)

A qualitative study of the factors that influence mothers when choosing drinks for their young children

Background The consumption of sweetened beverages is a known common risk factor for the development of obesity and dental caries in children and children consume sweet drinks frequently and in large volumes from an early age. The aim of this study was to examine factors that influence mothers when choosing drinks for their children. Method Semi-structured interviews (n = 32) were conducted with a purposive sample of mothers of young children from Victoria’s Barwon South Western Region (selected from a larger cohort study to include families consuming different types of water, and different socioeconomic status and size). Inductive thematic analysis was conducted on transcribed interviews. Results Several themes emerged as influencing child drink choice. Child age: Water was the main beverage for the youngest child however it was seen as more acceptable to give older children sweetened beverages. Child preference and temperament: influencing when and if sweet drinks were given; Family influences such as grandparents increased children’s consumption of sweet drinks, often providing children drinks such as fruit juice and soft drinks regardless of maternal disapproval. The Setting: children were more likely to be offered sweetened drinks either as a reward or treat for good behaviour or when out shopping, out for dinner or at parties. Conclusions Limiting intake of sweet drinks is considered an important step for child general and oral health. However, the choice of drinks for children has influences from social, environmental and behavioural domains, indicating that a multi-strategy approach is required to bring about this change