A decade of research on the phosphorus dynamics in Baltic Sea coastal areas using a combination of mathematical modelling, sediment surveys and time series of water quality data from monitoring programs has led to an improved understanding of processes controlling phosphorus turnover and coastal primary production. This paper presents a revised model for phosphorus turnover in non-tidal enclosed Baltic coastal areas. Using a new dataset from 500 sediment sampling stations it was possible to quantify and develop new simplified algorithms for sedimentary processes i.e. burial and erosion that did not decrease the model's predictive power. Our results indicate that erosion of old clays can be an important primary source to phosphorus water concentrations in enclosed coastal areas. A simple laboratory experiment using Common Duckweed (Lemna minor) supports to some extent that phosphorus originating from old clays is partly bioavailable and hence may influence the trophic state in the studied areas.
This chapter contains sections titled: Introduction A. astaci — Clonal Propagation and Host Range Spore Development Role of Pumilio-Like Proteins in Spore Development Extracellular Enzymes Host Immune Reactions toward A. astaci Future Perspectives References
Saprolegnia parasitica and Aphanomyces astaci are parasitic water moulds belonging to the Oomycetes. Despite their importance as parasites they are very little studied at the molecular level and the work described in this thesis was aimed at increasing the molecular knowledge of these organisms by cloning and characterising genes of potential importance for reproduction and pathogenicity.Stage-specific transcripts from Saprolegnia parasitica were isolated by differential display RT-PCR. One of the markers, puf1 encodes a putative mRNA binding protein which may be involved in post-transcriptional regulation of gene expression. S. parasitica puf1 is expressed exclusively in spore cysts that have not been determined for germination or repeated zoospore emergence indicating that the cyst stage has two phases, of about equal duration, which are physiologically and transcriptionally distinct. A similar expression pattern is observed in Aphanomyces spp. with different regulation of spore development and in the transcript is detected in both primary and secondary cysts.A putative chitinase AaChi1, was cloned from the crayfish plague fungus, Aphanomyces astaci. Analysis of chitinase activity and AaChi1 expression showed that chitinase in A. astaci is constitutively expressed in growing and sporulating mycelia, but absent in zoospores, a pattern which reflects the infectious life cycle of A. astaci. This expression pattern is conserved between the four known genotypes of A. astaci, in contrast to saprophytic and fish-pathogenic Aphanomyces spp. Genetic and physiological analysis were conducted on five strains of Aphanomyces, isolated from suspected outbreaks of crayfish plague in Spain and Italy. The strains are not virulent against freshwater crayfish, and RAPD PCR and ITS sequence analysis show that they are unrelated to the crayfish plague fungus, A. astaci.
Preparedness for bioterrorism is based on communication between people in organizations who are educated and trained in several disciplines, including law enforcement, health, and science. Various backgrounds, cultures, and vocabularies generate difficulties in understanding and interpretating terms and concepts, which may impair communication. This is especially true in emergency situations, in which the need for clarity and consistency is vital. The EU project AniBioThreat initiated methods and made a rough estimate of the terms and concepts that are crucial for an incident, and a pilot database with key terms and definitions has been constructed. Analysis of collected terms and sources has shown that many of the participating organizations use various international standards in their area of expertise. The same term often represents different concepts in the standards from different sectors, or, alternatively, different terms were used to represent the same or similar concepts. The use of conflicting terminology can be problematic for decision makers and communicators in planning and prevention or when handling an incident. Since the CBRN area has roots in multiple disciplines, each with its own evolving terminology, it may not be realistic to achieve unequivocal communication through a standardized vocabulary and joint definitions for words from common language. We suggest that a communication strategy should include awareness of alternative definitions and ontologies and the ability to talk and write without relying on the implicit knowledge underlying specialized jargon. Consequently, cross-disciplinary communication skills should be part of training of personnel in the CBRN field. In addition, a searchable repository of terms and definitions from relevant organizations and authorities would be a valuable addition to existing glossaries for improving awareness concerning bioterrorism prevention planning.
ABSTRACT The expression of spore-specific marker transcripts at different stages of the asexual life cycle of Saprolegnia parasitica was analyzed. One of the markers, designated puf1 , was found to be expressed transiently upon each of several cycles of zoospore encystment and reemergence. The transcript is induced immediately upon zoospore encystment and is rapidly lost when a cyst is triggered to germinate. In nongerminating cysts, puf1 is maintained until a time point when the cysts can no longer be triggered to germinate and thus have become determined for zoospore reemergence. The results show that the cyst stage has two phases, of about equal duration, which are physiologically and transcriptionally distinct and that the transcriptional machinery of oomycetes is also active in nongerminating spores. puf1 encodes a putative mRNA binding protein belonging to a conserved class of proteins including the Drosophila melanogaster Pumilio protein, Caenorhabditis elegans FBF, and Saccharomyces cerevisiae Puf5, all of which are involved in regulation of gene expression by posttranscriptional mechanisms.
