Gro?forschung mit anderen Namen

Naturwissenschaften Aktuell

Großforschung mit anderen Namen     

Activity of biotin-dependent and gaba metabolizing enzymes in chorionic villus samples: Potential for 1st trimester prenatal diagnosis

We have documented the presence of five mitochondrial enzymes in samples of chorionic villus tissue and measured the levels of activity. Three of the enzymes catalyse biotindependent reactions. These are propionyl-CoA carboxylase, 3-methylcrotonyl-CoA carboxylase and pyruvate carboxylase. the other enzymes. 4-aminobutyric acid aminotransferase and succinic semialdehyde dehydrogenase, are involved inthe degradation of the central inhibitory neurotransmitter GABA. Distinct diseases in whichthere is deficiency of each of these enzymes have been documented in man. Significant levels of activity were observed for all five enzymes in chorionic villus tissue. This methodology should permit early prenatal diagnosis of deficiencies of these enzymes by chorionic villus biopsy in the first trimester.     

The ladybird<Emphasis Type="Italic"> Thalassa saginata</Emphasis>, an obligatory myrmecophile of<Emphasis Type="Italic"> Dolichoderus bidens</Emphasis> ant colonies

The larvae and pupae of the ladybird Thalassa saginata develop inside colonies of the dolichoderine ant Dolichoderus bidens. This association is the first specific and obligatory relationship recorded between ants and ladybirds. The ants provide shelter and protection to the larvae but the diet of the latter remains unclear. The integration of T. saginata larvae into the ant colonies is achieved by mimicking the cuticular patterns of the ants brood. Moreover, the larvae secrete substances from their hairs and anal gland that are likely to enhance their attractiveness.     

Biomineralization in plants as a long-term carbon sink

Carbon sequestration in the global carbon cycle is almost always attributed to organic carbon storage alone, while soil mineral carbon is generally neglected. However, due to the longer residence time of mineral carbon in soils (10²–10⁶ years), if stored in large quantities it represents a potentially more efficient sink. The aim of this study is to estimate the mineral carbon accumulation due to the tropical iroko tree (Milicia excelsa) in Ivory Coast. The iroko tree has the ability to accumulate mineral carbon as calcium carbonate (CaCO₃) in ferralitic soils, where CaCO₃ is not expected to precipitate. An estimate of this accumulation was made by titrating carbonate from two characteristic soil profiles in the iroko environment and by identifying calcium (Ca) sources. The system is considered as a net carbon sink because carbonate accumulation involves only atmospheric CO₂ and Ca from Ca-carbonate-free sources. Around one ton of mineral carbon was found in and around an 80-year-old iroko stump, proving the existence of a mineral carbon sink related to the iroko ecosystem. Conservation of iroko trees and the many other biomineralizing plant species is crucial to the maintenance of this mineral carbon sink.     

Dystrophin protein and rflp analyis for fetal diagnosis and carrier confirmation of duchenne muscular dystrophy

A pregnant woman with indeterminate Duchenne muscular dystrophy (DMD) carrier status, but with DMD diagnosed in her deceased brother (unavailable for study), presented for prenatal diagnosis, intending to continue the pregnancy only if proven unaffected with DMD with near absolute certainty. Creatine kinase (CK) assays to clarify carrier status were inconclusive. Male sex in the fetus was identified, but DNA restriction fragment length polymorphism (RFLP) analysis was not yet available to this centre to investigate the possible transmission of the DMD gene, and the pregnancy was terminated. Tissue histology and dystrophin protein analysis demonstrated the absence of DMD. In a situation with proven maternal carrier status, future fetal inheritance of the opposite maternal X chromosome would indicate the presence of DMD. However, maternal carrier status remained in doubt through a second pregnancy, even with RFLP studies, and was finally established when dystrophin analysis confirmed the presence of DMD in the second fetus. Histologic findings are presented, contrasting features in the two fetuses. The value of dystrophin analysis for establishing the diagnosis of fetal DMD, in this case proving maternal carrier status in a difficult situation, and for demonstrating DMD gene:RFLP haplotype relationships is illustrated.     

Erratum

Naturwissenschaften Aktuell     

CLIMATE CHANGE AND NATURAL HAZARDS IN NORTHERN CANADA: INTEGRATING INDIGENOUS PERSPECTIVES WITH GOVERNMENT POLICY

A study of the relationship between natural hazards and climate change in the international context provides the background for a discussion of the expected changes. In the context of this global discussion, this paper reviews the current perspectives of those natural hazards that are likely to be influenced by climate change, using northern Canada as a regional case study. The northern implications of the United Nations Framework Convention on Climate Change are examined, including the status of climate change action by the northern territorial governments, the evolving role of indigenous people, and the responsibility for climate change impacts. The difficulties surrounding natural hazards research in remote locations, and the approaches of indigenous people to natural hazards are then presented. The paper concludes with a suggested policy approach for climate change and natural hazards in northern Canada, underscoring the need for more comprehensive adaptive strategies to complement the current tendency to focus on the mitigation of greenhouse gases produced in this region.     

Biodiversity and industry ecosystem management

The term biodiversity describes the array of interacting, genetically distinct populations and species in a region, the communities they comprise, and the variety of ecosystems of which they are functioning parts. Ecosystem health, a closely related concept, is described in terms of a process identifying biological indicators, end points, and values. The decline of populations or species, an accelerating trend worldwide, can lead to simplification of ecosystem processes, thus threatening the stability and sustainability of ecosystem services directly relevant to human welfare in the chain of economic and ecological relationships. The challenge of addressing issues of such enormous scope and complexity has highlighted the limitations of ecology-as-science. Additionally, biosphere-scale conflicts seem to lie beyond the scope of conventional economics, leading to differences of opinion about the commodity value of biodiversity and of the services that intact ecosystems provide. In the face of these uncertainties, many scientists and economists have adopted principles that clearly assign burdens of proof to those who would promote the loss of biodiversity and that also establish near-trump (preeminent) status for ecological integrity. Electric utility facilities and operations impact biodiversity whenever construction, operation, or maintenance of generation, delivery, and support facilities alters landscapes and habitats and thereby impacts species. Although industry is accustomed to dealing with broad environmental concerns (such as global warming or acid rain), the biodiversity issue invokes hemisphere-wide, regional, local, and site-specific concerns all at the same time. Industry can proactively address these issues of scope and scale in two main ways: first, by aligning strategically with the broad research agenda put forth by informed scientists and institutions; and second, by supporting focused management processes whose results will contribute incrementally to the broader agenda of rebuilding or maintaining biodiversity.     

Teaching for community environmental action: an alternative instructional model for environmental concepts and issues in schools

Summary Whether environmental education in the school curriculum is treated as a separate subject or as an interdisciplinary entity, the end product should be the same: to provide learners with the desire to preserve or develop optimum environments and to improve less desirable ones. In this endeavour, the learners must ultimately reach out to participate in community decisions and environmental management activities, for that is where the environmental problems abound. Moreover, young persons are generally more knowledgeable than many adults on environmental matters and are more aware of the effects of environmental degradation. When they participate in community environmental management, they may also develop unique and particularly dynamic qualities.Research worldwide suggests that very few teaching programmes encourage environmental participation. In Kenya teachers tend to use deductive teaching methods which do not encourage participation, although there may be ample opportunities in the local environment to facilitate such participation. A more refined, reconstructivist inquiry strategy, committed to the attainment of participative environmental education objectives is suggested. The approach, referred to as an operation-environment instructional model emphasizes action research, supported by a series of other vital stages, as fundamental to the agenda for environmental learning.William W. Toili possesses both Bachelor and Master's Degrees in Education from Nairobi as well as a Master's Degree from the University of Leeds, UK. He is currently a lecturer in Environmental Education at Maseno University College.