The Potted-Plant Microcosm Substantially Reduces Indoor Air VOC Pollution: I. Office Field-Study

Volatile organic compounds (VOCs) are major contaminants of indoor air, with concentrations often several times higher than outdoors. They are recognized as causative agents of “building-related illness” or “sick-building syndrome”. Our previous laboratory test-chamber studies have shown that the potted-plant/root-zone microorganism microcosm can eliminate high concentrations of air-borne VOCs within 24 hours, once the removal response has been induced by an initial dose. However, the effectiveness of the potted-plant microcosm in ‘real-world’ indoor spaces has never previously been tested experimentally. This paper reports the results of a field-study on the effects of potted-plant presence on total VOC (TVOC) levels, measured in 60 offices (12 per treatment), over two 5–9 week periods, using three planting regimes, with two ‘international indoor-plant’ species. Fourteen VOCs were identified in the office air. When TVOC loads in reference offices rose above 100 ppb, large reductions, of from 50 to 75% (to <100 ppb), were found in planted offices, under all planting regimes The results indicate that air-borne TVOC levels above a threshold of about 100 ppb stimulate the graded induction of an efficient metabolic VOC-removal mechanism in the microcosm. Follow-up laboratory dose-response experiments, reported in the following paper, confirm the graded induction response, over a wide range of VOC concentrations. The findings together demonstrate that potted-plants can provide an efficient, self-regulating, low-cost, sustainable, bioremediation system for indoor air pollution, which can effectively complement engineering measures to reduce indoor air pollution, and hence improve human wellbeing and productivity.     

The buffer effect of non-breeding birds and the timing of farmland bird declines

Breeding territoriality in birds means that a certain proportion of the adult population may breed in suboptimal habitats or not breed at all. Non-breeding birds, or floaters, can have a `buffer effect' on breeding population size. Farmland bird declines in Britain are measured and analysed in terms of numbers of territory-holding birds. We use a population dynamics model to illustrate how, because of the buffer effect of floaters, there can be a time lag between the start of total population decline and detectable breeding population decline. Differences in the timing of declines of closely related farmland birds could therefore be due to slight differences in their population dynamics, rather than differences in their response to agricultural change.     

Development and practical test of a weighable groundwater lysimeter for floodplain sites

Presently, the soil water balance of flood‐influenced soils in fluvial plains is insufficiently described. The new development of a weighable groundwater lysimeter is the basis for recording the water‐balance components precipitation, evapotranspiration, groundwater recharge, capillary rise, and interaction with the water course. Soil‐hydrologic measuring setups at two floodplain sites of the Elbe river serve for direct comparability of lysimeter measurements with data obtained on site. A groundwater control was designed for lysimeters that automatically adjusts the current groundwater level at the floodplain measuring setups and quantifies inflow into or outflow from the lysimeter. It turned out that the lysimeter developed is capable of identifying the individual water‐balance quantities at high accuracy. Contrary to previous assumptions, it was possible to prove groundwater recharge for the floodplain sites.     

Antifungal proteins in commercial hybrids and elite sorghums

The antifungal proteins (AFP) in the caryopsis of commercial and elite sorghums grown in several environments were related to grain mold resistance. Previous studies revealed that improved grain mold resistance was correlated with higher levels of AFP at combine harvest maturity [50 days after anthesis (DAA)] or with better retention of AFP after physiological maturity (30 DAA). Commercial hybrids and public parental lines and hybrids were grown in College Station, TX, during 2000, 2001, and 2002. Samples of caryopses were collected at 30 and 50 DAA, and caryopsis proteins were extracted, blotted, identified with immunoassays, and quantified for two AFP (chitinase and sormatin). Sorghums varied in amounts of AFP and their ability to retain AFP after physiological maturity. The environment in 2002 was conducive for fungal deterioration of grain, and a wide range of AFP and grain molding was observed at harvest maturity. High levels of AFP and low levels of grain molding were observed in non-mold-conducive environments in 2000 and 2001. Commercial and elite sorghums with higher levels and increased retention of AFP had less grain molding in the mold-conducive environment.     

Light-stimulated 14CO2 uptake and acetylene reduction by bacteriochlorophyll containing stem nodule isolate BTAi 1

Summary Bradyrhizobial strain BTAi 1 nodulates both stems and roots of Aeschynomene spp. Previous work has shown that it contains bacteriochlorophyll a and forms photosynthetic reaction centers, and has provided indirect evidence of photosynthesis by bacteroids within stem nodules. Here we report physiological and biochemical characteristics of BTAi 1 ex planta, which also suggest the presence of photosynthetic activity. Light-stimulated uptake of ¹⁴CO₂ by BTAi 1 was detected at all stages of growth. Inhibitors of photosynthesis, 1,10-orthophenanthroline and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), and the uncoupler NH₄Cl, immediately suppressed light-driven ¹⁴CO₂ uptake and increased O₂ uptake. BTAi 1 is strictly aerobic and was unable to grow without organic C even in the light; also, it was unable to grow chemoautotrophically in an atmosphere enriched with H₂ and CO₂. In micro-aerobic conditions, strain BTAi 1 expressed acetylene reducing activity ex planta in an N-free medium. The highest rates of light-stimulated ¹⁴CO₂ uptake and acetylene-reducing activity occurred during the exponential and early stationary phases of growth. Acetylene-reducing rates at a low glucose concentration were increased following a light-dark cycle in comparison with continuous dark conditions.     

Identification of 4-O-5'-coupled diferulic acid from insoluble cereal fiber

The extracts of saponified cereal fibers of whole grains of corn (Zea mays cv. microsperma KOERN.), wheat (Triticum aestivum L.), spelt (Triticum spelta L.), and rice (Oryza sativa L.) were investigated for dehydrodimers of ferulic acid using gas-liquid chromatography (GLC) with mass spectrometric detection (GLC-MS) and flame ionization detection (GLC-FID). In addition to the 8,5'-, 8, 8'-, 5,5'-, and 8-O-4'-coupled diferulic acids previously identified from other plant materials the 4-O-5'-coupled diferulic acid (E)-3-[4-[(E)-2-carboxyvinyl]-2-methoxyphenoxy]-4-hydroxy-5-methoxyci nnamic acid (4-O-5'-DFA) was identified in all fibers investigated. This new diferulate was authenticated by comparison of its mass spectrum and its relative GLC retention time with those of the synthesized compound. Semiquantitative determination of 4-O-5'-DFA showed that it is present at 8-30 microg/g, approximately 70-100 times lower concentrations than the sum of 8,5'-coupled diferulic acids, the major diferulic acids in the investigated fibers.     

Positional syntenic cloning and functional characterization of the mammalian circadian mutation tau

The tau mutation is a semidominant autosomal allele that dramatically shortens period length of circadian rhythms in Syrian hamsters. We report the molecular identification of the tau locus using genetically directed representational difference analysis to define a region of conserved synteny in hamsters with both the mouse and human genomes. The tau locus is encoded by casein kinase I epsilon (CKIepsilon), a homolog of the Drosophila circadian gene double-time. In vitro expression and functional studies of wild-type and tau mutant CKIepsilon enzyme reveal that the mutant enzyme has a markedly reduced maximal velocity and autophosphorylation state. In addition, in vitro CKIepsilon can interact with mammalian PERIOD proteins, and the mutant enzyme is deficient in its ability to phosphorylate PERIOD. We conclude that tau is an allele of hamster CKIepsilon and propose a mechanism by which the mutation leads to the observed aberrant circadian phenotype in mutant animals.     

Immunotherapy: bewitched, bothered, and bewildered no more

The field of immunotherapy holds clear promise not only for the development of new approaches to cancer and other diseases, but also for providing fundamental insight into the human immune response. In order for this promise to be realized, however, the scientific community must overcome an array of challenges. These challenges reflect not only the difficulties inherent in conducting investigations in human patients, but also difficulties created by the culture and practice of our own institutions, reward structure, and funding mechanisms. We suggest steps to be taken to reinvigorate basic research in human subjects as part of the mainstream of science.     

Rooted in grass: Challenging patterns of knowledge exchange as a means of fostering social change in a southeast Minnesota farm community

By convening a multidisciplinary team(the Monitoring Team) that included farmers,university and agency researchers, andnon-profit staff; a small group of farmers insoutheast Minnesota, U.S.A., bolstered thelegitimacy of the sustainable agriculturemovement. Through the experience of forming ateam and working with individuals who operatedwithin the mainstream knowledge paradigm,farmers gained validation of their knowledgeabout farming, while researchers came to valuealternative knowledge systems. In the contextof a socially embedded movement, farmers wereempowered by sharing their knowledge withresearchers, and ultimately contributed to thesustainable agriculture movement by challengingtraditional patterns of knowledge exchange.