The relationship between Pseudo-nitzschia (Peragallo) and domoic acid in Scottish shellfish

The diatom genus Pseudo-nitzschia (Peragallo) associated with the production of domoic acid (DA), the toxin reposnsible for amnesic shellfish poisoning, is abundant in Scottish waters. A two year study examined the relationship between Pseudo-nitzschia cells in the water column and DA concentration in blue mussels (Mytilus edulis) at two sites, and king scallops (Pecten maximus) at one site. The rate of DA uptake and depuration differed greatly between the two species with M. edulis whole tissue accumulating and depurating 7 μg g⁻¹ (now expressed as mg kg⁻¹) per week. In contrast, it took 12 weeks for DA to depurate from P. maximus gonad tissue from a concentration of 68 μg g⁻¹ (now mg kg⁻¹) to <20 μg g⁻¹ (now mg kg^‐1). The DA depuration rate from P. maximus whole tissue was <5% per week during both years of the study. Correlations between the Pseudo-nitzschia cell densities and toxin concentrations were weak to moderate for M. edulis and weak for P. maximus. Seasonal diversity on a species level was observed within the Pseudo-nitzschia genus at both sites with more DA toxicity associated with summer/autumn Pseudo-nitzschia blooms when P. australis was observed in phytoplankton samples. This study reveals the marked difference in DA uptake and depuration in two shellfish species of commercial importance in Scotland. The use of these shellfish species to act as a proxy for DA in the environment still requires investigation.     

The Ordovician-Silurian boundary stratotype: consequences of its approval by the IUGS

Lespérance, Pierre J., Barnes, Christopher R., Berry, William B. N., Boucot, Arthur J. & Mu En-zhi 1987 07 15: The Ordovician-Silurian boundary stratotype: consequences of its approval by the IUGS.
The Ordovician-Silurian stratotype at Dob's Linn, Scotland is the second systemic boundary approved by the International Union of Geological Sciences (IUGS). A review of the internationally accepted criteria required of a stratotype shows that few of these are possessed by the Dob's Linn section. The strongest attribute of the section is the presence of zonal graptolites, although the boundary is recognized primarily on a single biological event (base of acuminatus Zone) for which the evolutionary relationships of the taxa are not established. In approving this boundary proposal in 1985, which received only simple majority support within the Ordovician-Silurian Boundary Working Group (OSBWG) and which fails to meet most of the accepted prerequisites for a stratotype, the International Commission on Stratigraphy (ICS) and the IUGS have established an unfortunate precedent. It follows that future systemic boundaries need not meet the accepted standards. It raises serious questions on the assessment and voting procedures of the International Commission on Stratigraphy and on the credence accorded the recommendations developed by the International Subcommission on Stratigraphic Classification of IUGS.     

Shoot regeneration after fire or freezing temperatures and its relation to plant life-form for some heathland species

Shoot regeneration after prescribed burning or following the freezing temperatures of winter was monitored for nineteen heathland species present in an Arctostaphyleto-Callunetum community in northeast Scotland. Species whose renewal buds were near the surface of the ground started to grow earlier in the spring than species with renewal buds above the surface, but grouping species according to the position of their renewal bud (i.e. their life-form) did not account for all of the interspecific variation apparent. In the case of shoot regeneration after fire, species whose renewal buds were destroyed by fire because they were above-ground started to regenerate about the same time as species with belowground buds, protected from fire, but reached their maximum frequency of occurrence later. Grouping species by life-form was of limited value as a means of interpreting this interspecific variation in the timing of shoot regeneration after fire. It would be unwise to use plant life-form as the sole basis for interpreting or predicting a species' response to temperature stress when extreme temperatures occur regularly, as they do in heathland. The possible use of other plant traits to interpret and predict interspecific variation in the regeneration rate of heathland plants is discussed.Nomenclature follows Tutin et al. (1964–1980) for vascular plants. Acknowledgements. The Nature Conservancy Council and Mr J. J. Humphries kindly allowed Dinnet Moor to be used for the work presented here. One of us (RJR) received financial support for field work from the Natural Sciences and Engineering Research Council of Canada.     

An approach to the identification of adenosine''s inhibitory site on adenylate cyclase

The separate and combined effects of molybdate and dithiothreitol on the stability of human uterine 9 S estrogen receptor were studied. Maximal, short-term, protection of the 9 S estrogen receptor was achieved by the joint inclusion of both stabilizing agents in cytosol buffers. This molybdate—dithiothreitol-mediated stability was dependent on reducing agent concentration inferring sulphydryl involvement in 9 S receptor protection by molybdate. The study also showed that molybdate—dithiothreitol could not prevent the gradual decay of the 9 S estrogen receptor to the 4 S form in cytosols stored at 4°C over prolonged periods.     

The cryopreservation of mouse leukemic cells. I. Effects on drug resistance and the patterns of nucleic acid metabolism.

Cultured L1210 lymphocytic leukemic cells resistant to cytosine arabinoside or Cytoxan were frozen under different conditions for up to 5 months and transplanted into recipient mice. Biochemical determinations including DNA, total RNA and drug resistance suggested that the more rapid, less expensive method of freezing mouse leukemic cells enables good retention of each parameter. Examination of cellular and subcellular RNA fingerprints indicated several alterations in the localizations f certain subspecies of RNA. Nonetheless, all cells retained their overall viability and the capacity to induce leukemia in CDF₁ mice.     

Earliest vertebrate embryos in the fossil record (Middle Devonian,Givetian)

Serial sectioning of a nodule encapsulating an adult specimen of the arthrodire placoderm Watsonosteus fletti from the Eday Flagstone Formation (Givetian) in the Orcadian Basin of northern Scotland has revealed the presence of a number of embryos within the adult. This specimen represents the oldest known record of fossilized vertebrate embryos. Thin sections of two of the slices have revealed the detailed histological structure of embryonic plates in placoderms, showing that as previously deduced from visual examination, the outer and inner layers were the first to form. Gut contents preserved near the embryos show that the species had a varied diet, with dermal bone fragments from sarcopterygians and placoderms.     

Isothecium myosuroides var. brachythecioides (Dixon) Braithw. reinstated as a species,I. interludens Stirt.

The taxon currently known as Isothecium myosuroides var. brachythecioides (Dixon) Braithw. is reinstated as a species, I. interludens Stirt., the name originally assigned by Stirton when it was first described. The morphological characters separating I. myosuroides s.s. and I. interludens are summarised. The sporophytes of I. interludens, described here for the first time, differ in shape, and pattern of exothecial cells from those of I. myosuroides. A molecular analysis based on variation of the ITS region shows that I. holtii Kindb. and I. alopecuroides (Lam. ex Dubois) Isov. are not monophyletic, calling for a re-assessment of these species, whereas the monophyly of the other species, including I. interludens, cannot be rejected. The analysis failed, however, to yield molecular synapomorphies for I. interludens and other species within I. myosuroides s.l., which we interpret as the incomplete sorting of alleles among recently evolved species. Isothecium interludens is a European endemic with a hyperoceanic temperate distribution. Its nested position within a clade including the two Macaronesian endemics I. prolixum (Mitt.) M.Stech and I. montanum Draper, Hedenäs, M.Stech, T.Lopes & Sim-Sim is suggestive of a Macaronesian origin, in line with the idea that the European Atlantic fringe flora assembled during the course of the last interglacial from Macaronesian ancestors. Isothecium therefore offers a model of prime importance for the study of ongoing speciation in mosses.     

Looking up in Scotland? Multinationalism,multiculturalism and political elites

At a time when all the political parties of Scotland are trying to establish a persuasive vision of the nation, inquiry into where ethnic and racial minorities fit into these debates provides one understudied means of bridging literatures on multinationalism and multiculturalism. Focusing especially on the lesser known question of how elite political actors are positioning minorities within projects of nation-building, this article draws upon original empirical data in which three predominant clusters emerge. The first centres on an aspirational pluralism, in so far as political elites are less inclined – in contrast to counterparts in some other minority nations – to place ethnically determined barriers on membership of Scottish nationhood. The second concerns the competing ways in which the legacy of Scotland's place in the British Empire is appropriated by actors of different political hues, and so assumes a multiform role. The third cluster points to potential limitations in minority claims-making and recognition, especially in terms of formal multilingualism and corporate multifaithism, something that may partly be explained by the tension between multinationalism and multiculturalism. Taken together, the article illustrates how elite political actors can play a vital role in ensuring that appeals to nationhood in Scotland can be meaningfully calibrated to include minorities too.     

Legal Traditions,Environmental Awareness,and a Modern Industry: Comparative Legal Analysis and Marine Aquaculture

In the interests of increasing fish production globally, alleviating global poverty, and income generation, marine aquaculture has seen worldwide expansion over the past few decades. However, this expansion has been matched by growing concerns over its environmental impacts. This article utilizes comparative legal analysis to explore the legal systems of governance for the environmental performance of marine aquaculture in four case study countries. Two are members of the European Community (Scotland, as part of the United Kingdom, and Greece), one is a recent accession country (Slovenia), and the fourth is closely linked to the European Community albeit geographically and legally disparate (Israel).