Geochemical changes recorded in Lynch's Crater, Northeastern Australia, over the past 50 ka

There are many geochemical reconstructions of environmental change in the mid and high latitudes but relatively few in the tropical latitudes, despite their considerable potential for reconstructing environmental processes that cannot be identified using more traditional proxies. Here we present one reconstruction of environmental change for the tropics. This reconstruction covers the past 50 ka using a suite of geochemical data from the high-resolution sequence of Lynch's Crater in northeast Queensland, Australia, a region highly sensitive to El Niño-Southern Oscillation (ENSO) activity. The 23 major oxides and trace elements measured could be summarised by extracting three axes using principal components analysis (accounting for 72% of the variability). The data indicate that the greatest variability in the geochemical data accounted for erosional activity within the catchment that was associated with past changes in the frequency of ENSO activity (though this was less sensitive during wetter periods, probably as a result of buffering by high vegetation cover). The remaining variability was largely explained by elements that form complexes with organic compounds (e.g., humic acids) and those that are important nutrients for specific vegetation types (and therefore a measure of vegetation distribution). For more detailed reconstructions, further work is required to disentangle the complex controls of elements within sedimentary sequences.

Degradation products of clavulanic acid promote clavulanic acid production in cultures of Streptomyces clavuligerus

The role of clavulanic acid, an unstable antibiotic produced by Streptomyces clavuligerus, in biomass accumulation and production of clavulanic acid in batch cultures of the organism was examined. The organism was grown in a medium containing either 20 g/l lysine, 1 g/l lysine or 1 g/l lysine supplemented with degraded clavulanic acid as nitrogen sources. Biomass accumulation was highest in cultures grown with supplemented degraded clavulanic acid and reached a maximum of 2.2 g/l, compared with 1.5 g/l when lysine only was used. The yield coefficient for clavulanic acid production was again highest in cultures grown with supplemented degraded clavulanic acid, with a Y-p/x, value of 2 mg/g compared with Y-p/x value of 1.5 mg/g in 20 g/l lysine. No clavulanic acid was produced in cultures containing non-supplemented 1 g/l lysine. Non-degraded clavulanic, acid was added at 60 h to non-producing cultures of the organism containing 1 g/l lysine only. Clavulanic acid concentration immediately decreased on addition from 0.04 g/l over a period of 20 h, then remained constant at 0.02 g/l for a further 30 h until the end of the cultivation. This suggests that the rate of degradation was equivalent to the rate of production of clavulanic acid following a period of initial additive degradation. These results indicate that clavulanic acid is both produced and degraded in cultures of S. clavuligerus and that the products of degradation are used by the organism, resulting in further production of the antibiotic. (C) 2003 Elsevier Inc. All rights reserved.

Permanent changes in growth and physiology of Bacillus subtilis ToC46 after loss of a recombinant plasmid

The physiology and growth of plasmid-bearing Bacillus subtilis carrying plasmid pPFF1, the non-transformed host, and cells after loss of the plasmid (so-called plasmid-cured cells) were investigated. It was found that, following plasmid loss, cells exhibited phenotypic characteristics different from those of the non-transformed host strains. Compared to plasmid-bearing cells and non-transformed host cells, an approximate 25% increase in the maximum specific growth rate and a more rapid increase in total RNA per unit cell mass were observed in plasmid-cured cells. The total enthalpy associated with irreversible denaturation events was determined in whole cells by differential scanning calorimetry. This showed higher enthalpies for plasmid-cured cells compared with the non-transformed host, which suggests increased ribosome numbers. The result from cellular DNA hybridisation suggests that there was no direct evidence of plasmid integration into the host chromosome. (C) 2004 Elsevier Inc. All rights reserved.

Growth inhibition of mammalian cells by synthetic and natural photosensitising agents

A mammalian cell line, J774, was susceptible to both synthetic and natural photosensitising agents after irradiation with long-wave ultraviolet light. Both UV-A light and psoralen did not affect cell growth individually; a reduction in visual confluency was achieved only when psoralen and UV-A light were used in combination. The maximum visual confluency decreased by 55% when 50 ppm psoralen was added to a growing culture and irradiated with UV light for 3 min. Decreasing the UV-A exposure times from 3 min to 3 s did not greatly affect the maximum total visual confluence reached using different synthetic psoralen concentrations, but did affect the rate at which cell death occurred. The 3 min exposure time resulted in a rapid decrease in cell numbers in comparison to 3 s exposure time. Synthetic psoralen was found to have an increasing photosensitising activity with increasing concentration using a logarithmic shift between 0.5 ppm and 50 ppm. A visual confluency of 45% was achieved using concentrations of 50 ppm psoralen, and 70% visual confluency using 0.5 ppm. Natural mixtures of furanocoumarins containing psoralens, obtained from two separate parsley sources, were found to have greater efficacy at inhibiting the growth cycle of the cells when compared to the synthetic psoralen.

Differences in perceived risks and benefits of herbal, over-the-counter conventional, and prescribed conventional, medicines, and the implications of this for the safe and effective use of herbal products

Objectives: To investigate people's views about the efficacy and specific risks of herbal, over-the-counter (OTC) conventional, and prescribed conventional medicines, and their likelihood of taking a second (herbal or OTC conventional) product in addition to a prescribed medicine. Methods: Experiment 1 (1 factor within-participant design); Experiment 2 (1 factor between-participant design). Convenience samples of general population were given a hypothetical scenario and required to make a number of judgements. Results: People believed herbal remedies to be less effective, but less risky than OTC and prescribed conventional medicines. Herbal medicines were not seen as being safer simply because of their easier availability. Participants indicated that they would be more likely to take a herbal medicine than a conventional OTC medicine in addition to a prescribed medicine, and less likely to consult their doctor in advance. Conclusion: People believe that herbal medicines are natural and relatively safe and can be used with less caution. People need to be given clear information about the risks and benefits of herbal medicines if they are to use such products safety and effectively. (c) 2006 Elsevier Ltd. All rights reserved.

Urban conservation areas and sustainable development: exploring the relationship

With increasing emphasis being placed on concentrating development in urban areas and improving the quality of life in British cities and towns, the importance of accommodating necessary development without compromising the valued heritage and architectural quality of urban areas is now becoming central to sustainable urban development. Urban conservation policy and practice has the potential to contribute to this and other aspects of sustainability. This paper explores this contribution and develops an analytical framework which draws out the key linkages between conservation area policy and sustainable development. The framework is then used to research the potential and actual contribution of urban conservation policy and practice in England, using a selective survey and two case studies (i.e. Winchester and Basingstoke). The main conclusions from the research are that: Conservation area policy can make a significant contribution to the principles of sustainable development; Most local planning authorities in England have not fully woken-up to this potential and have not developed policies or practices to address it; and Urban conservation policy needs to develop a more proactive approach in which local planning authorities actively guide and encourage new development with regard to use, design, layout, methods of construction, materials and energy efficiency.

Analyzing lateral root development: how to move forward

Roots are important to plants for a wide variety of processes, including nutrient and water uptake, anchoring and mechanical support, storage functions, and as the major interface between the plant and various biotic and abiotic factors in the soil environment. Therefore, understanding the development and architecture of roots holds potential for the manipulation of root traits to improve the productivity and sustainability of agricultural systems and to better understand and manage natural ecosystems. While lateral root development is a traceable process along the primary root and different stages can be found along this longitudinal axis of time and development, root system architecture is complex and difficult to quantify. Here, we comment on assays to describe lateral root phenotypes and propose ways to move forward regarding the description of root system architecture, also considering crops and the environment.