Darkness visible: reflections on underground ecology

1 Soil science and ecology have developed independently, making it difficult for ecologists to contribute to urgent current debates on the destruction of the global soil resource and its key role in the global carbon cycle. Soils are believed to be exceptionally biodiverse parts of ecosystems, a view confirmed by recent data from the UK Soil Biodiversity Programme at Sourhope, Scotland, where high diversity was a characteristic of small organisms, but not of larger ones. Explaining this difference requires knowledge that we currently lack about the basic biology and biogeography of micro-organisms. 2 It seems inherently plausible that the high levels of biological diversity in soil play some part in determining the ability of soils to undertake ecosystem-level processes, such as carbon and mineral cycling. However, we lack conceptual models to address this issue, and debate about the role of biodiversity in ecosystem processes has centred around the concept of functional redundancy, and has consequently been largely semantic. More precise construction of our experimental questions is needed to advance understanding. 3 These issues are well illustrated by the fungi that form arbuscular mycorrhizas, the Glomeromycota. This ancient symbiosis of plants and fungi is responsible for phosphate uptake in most land plants, and the phylum is generally held to be species-poor and non-specific, with most members readily colonizing any plant species. Molecular techniques have shown both those assumptions to be unsafe, raising questions about what factors have promoted diversification in these fungi. One source of this genetic diversity may be functional diversity. 4 Specificity of the mycorrhizal interaction between plants and fungi would have important ecosystem consequences. One example would be in the control of invasiveness in introduced plant species: surprisingly, naturalized plant species in Britain are disproportionately from mycorrhizal families, suggesting that these fungi may play a role in assisting invasion. 5 What emerges from an attempt to relate biodiversity and ecosystem processes in soil is our extraordinary ignorance about the organisms involved. There are fundamental questions that are now answerable with new techniques and sufficient will, such as how biodiverse are natural soils? Do microbes have biogeography? Are there rare or even endangered microbes

Psychiatric and medical features of near fatal asthma.

BACKGROUND--The associations between psychiatric caseness, denial, and self reported measures of handicap and morbidity due to asthma in patients suffering a near fatal attack of asthma have not been fully explored. METHODS--Seventy seven consecutive subjects who presented to Adelaide teaching hospitals with a near fatal attack of asthma were assessed with a validated semi-structured interview following discharge from hospital. RESULTS--43% of the patients scored > or = 5 on the GHQ-28 questionnaire. There was a positive correlation between GHQ-28 score and limitation to daily activities due to asthma, and between GHQ-28 score and days lost from work, school or usual daily activities, both of which were retained after adjusting for age and sex. Asthma severity did not show a clear association with GHQ-28 score. The asthmatic patients reported high levels of denial, 57% scoring more than 3 out of 5 on the denial scale of the Illness Behaviour Questionnaire. Presentation with a history of progressive respiratory distress was negatively associated with denial score. This persisted after adjustment for age and sex--that is, those with high denial scores were more likely to report presentation as sudden collapse than progressive respiratory distress. CONCLUSIONS--Psychiatric caseness (GHQ score > or = 5) is associated with high levels of morbidity in asthmatic patients who survive a near fatal attack of asthma. High levels of denial in asthmatic subjects may be life threatening. The link between morbidity associated with asthma and psychiatric features, along with other psychosocial issues, warrants further investigation. A broader paradigm than the traditional medical model should be considered when assessing patients with asthma