Patrick Fitzpatrick

Assessment of the impact of organic pollutants on goby (Zosterisessor ophiocephalus) and mussel (Mytilus galloprovincialis) from the Venice Lagoon, Italy: Biochemical studies

The use of cytochrome P4501A (CYP1A) and other measurements as biomarkers was investigated in liver of goby (Z. ophiocephalus) and digestive gland of mussel (M. galloprovincialis) from several sites in the Venice lagoon as part of the UNESCO-MURST Venice Lagoon Ecosystem Project. Most tissue contaminants (PAHs, PCBs, DDTs) and biochemical measurements varied seasonally. Elevated 7-ethoxyresorufin O-deethylase activity and CYP1A-protein levels in goby were correlated with high tissue contaminant levels at the industrial Porto Marghera site. On occasions, activities of the antioxidant enzymes catalase and putative DT-diaphorase (resorufin reductase activity) in male but not female goby were also higher at Porto Marghera than other sites, but no differences were seen in Superoxide dismutase (SOD) activity. A range of measurements (SOD, catalase, NADPH-cytochrome c reductase and glutathione S-transferase activities, P450 and ‘418-peak’ contents) in mussel showed little difference between sites. However, indications were obtained of elevated levels of CYP1A1-like mRNA, CYP1A-like protein and metabolism of benzo[a]pyrene to free metabolites in mussels from the Venice lagoon compared to a site in the Adriatic Sea. The studies demonstrate the usefulness of CYP1A as a biomarker for organic pollution in fish and indicate some potential for its application in molluscs.

Assessment of a glutathione S-transferase and related proteins in the gill and digestive gland of Mytilus edulis (L.), as potential organic pollution biomarkers

The response of the glutathione S-transferase (GST, EC 2.5.1.18) and related proteins of Mytilus edulis to environmental pollution load was assessed. Mussels were reciprocally transplanted between an industrial estuary (Douglas), a rural estuary (Youghal) and a m arine site (Bantry). In addition, m ussels were sam pled along a pollution gradient in an estuary receiving leather tannery effluent (Colligan). These latter m ussels were previously shown to be subject to oxidative stress resulting from the discharges. GST specific activity of cytosolic extracts from the gill and digestive gland tissues was determ ined for all anim als. Specific activity was shown to vary significantly in anim als from different sites, with highest specific activity always observed in sam ples (local and transplanted) taken from the industrial site. By com parison, the m ussels exposed to tannery discharges displayed no significant alteration in GST specific activity. Total intracellular glutathione (GSH) was also determ ined for sam ples taken from the Douglas and Youghal estuaries but no correlation with pollution load was observed. Using FPLC analysis, we observed no specific effect on the relative levels of the GST and the individual GST related proteins in gill or digestive gland sam ples from local or reciprocally transplanted anim als from Douglas or Youghal. The increase in GST specific activity observed in samples from the industrial estuary are indicative of a possible, specific inductive agent at this site. The results from the tannery site, by com parison, indicate that general oxidative stress does not result in elevated G ST specific activity in M. edulis.The response of the glutathione S-transferase (GST, EC 2.5.1.18) and related proteins of Mytilus edulis to environmental pollution load was assessed. Mussels were reciprocally transplanted between an industrial estuary (Douglas), a rural estuary (Youghal) and a m arine site (Bantry). In addition, m ussels were sam pled along a pollution gradient in an estuary receiving leather tannery effluent (Colligan). These latter m ussels were previously shown to be subject to oxidative stress resulting from the discharges. GST specific activity of cytosolic extracts from the gill and digestive gland tissues was determ ined for all anim als. Specific activity was shown to vary significantly in anim als from different sites, with highest specific activity always observed in sam ples (local and transplanted) taken from the industrial site. By com parison, the m ussels exposed to tannery discharges displayed no significant alteration in GST specific activity. Total intracellular glutathione (GSH) was also determ ined fo...

On the key equation

We consider the set M={(a, b):a≡bh mod x2t} of all solutions of the key equation for alternant codes, where h is the syndrome polynomial. In decoding these codes a particular solution (ω, σ)∈M is sought, subject to ω and σ being relatively prime and satisfying certain degree conditions. We prove that these requirements specify (ω, σ) uniquely as the minimal element of M (analogous to the monic polynomial of minimal degree generating an ideal of F[x]) with respect to a certain term order and that, as such, (ω, σ) may be determined from an appropriate Grobner basis of M. Motivated by this and other variations of the key equation (such as that appropriate to errors-and-erasures decoding) we derive a general algorithm for solving the congruence a≡bg mod xn for a range of term orders defined by the conditions on the particular solution required. Our techniques provide a unified approach to the solution of these key equations

Separation of multiple forms of glutathione S-transferase from the Blue Mussel, Mytilus edulis

1. Glutathione S-transferase isoenzymes from Mytilus edulis and M. galloprovincialis have been partially purified by glutathione-sepharose affinity chromatography followed by Mono Q anion exchange fast protein liquid chromatography (f.p.l.c.). 2. The tissue distribution of glutathione S-transferase in M. edulis has been studied. Using 1-chloro-2,4-dinitrobenzene as substrate, highest specific activity is observed in the gill, the main feeding organ. Affinity-purified extracts of this organ give a characteristic f.p.l.c. profile. A similar profile is obtained with affinity-purified extracts of the digestive gland of M. galloprovincialis. 3. The subunit structure of the purified isoenzymes has been studied by SDS polyacrylamide gel electrophoresis and reversed-phase h.p.l.c. The subunits have similar molecular weights and h.p.l.c. retention times to rat glutathione S-transferases.

Studies on Isoenzymes of Glutathione S-Transferase in the Digestive Gland of Mytilus galloprovincialis With Exposure to Pollution

Abstract The possible utility of glutathione S-transferase isoenzymes in affinity purified extracts of digestive gland from Mytilus galloprovincialis as indicators of exposure to organic pollution has been assessed by fast protein liquid chromatography (FPLC) using a Mono-Q ion exchange column. Four main peaks of protein (isoenzymes 1–4) were detected in these chromatographic studies all of which displayed detectable catalytic activity with 1-chloro-2,4-dinitrobenzene and glutathione as substrates. The bulk of the activity with these substrates was associated with isoenzyme 1. The specific activity of cytosolic extracts from six sites in Venice Lagoon and the Adriatic Sea (UNESCO-MURST Venice Lagoon Ecosystem Project) decreased slightly with increasing tissue levels of chemical contaminants (hydrocarbons, PCBs and organochlorines). FPLC of affinity purified extracts from three of these sites was used to assess the possible variation in the levels of individual isoenzymes relative to pollution status. No difference was observed in the levels of these isoenzymes.

Gröbner Bases over Galois Rings with an Application to Decoding Alternant Codes

We develop a theory of Grobner bases over Galois rings, following the usual formulation for Grobner bases over finite fields. Our treatment includes a division algorithm, a characterization of Grobner bases, and an extension of Buchberger?s algorithm. One application is towards the problem of decoding alternant codes over Galois rings. To this end we consider the module M= {(a, b) :aS?b modxr} of all solutions to the so-called key equation for alternant codes, where S is a syndrome polynomial. In decoding, a particular solution (?, ?) ?M is sought satisfying certain conditions, and such a solution can be found in a Grobner basis of M. Applying techniques introduced in the first part of this paper, we give an algorithm which returns the required solution.

Gröbner bases and combinatorics for binary codes

In this paper we introduce a binomial ideal derived from a binary linear code. We present some applications of a Gröbner basis of this ideal with respect to a total degree ordering. In the first application we give a decoding method for the code. In the second one, by associating the code with the set of cycles in a graph, we can solve the problem of finding all codewords of minimal length (minimal cycles in a graph), and show how to find a minimal cycle basis. Finally we discuss some results on the computation of the Gröbner basis.

Fully Parameterizable Elliptic Curve Cryptography Processor over GF(2)

In this paper we present an Elliptic Curve Point Multiplication processor over base fields GF(2m), suitable for use in a wide range of commercial cryptography applications. Our design operates in a polynomial basis is fully parameterizable in the irreducible polynomial and the chosen Elliptic Curve over any base Galois Field up to a given size. High performance is achieved by use of a dedicated Galois Field arithmetic coprocessor implemented on FPGA. The underlying FPGA architecture is used to increase calculation performance, taking advantage of the properties of this kind of programmable logic device to perform the large number of logical operations required. We discuss the performance of our processor for different Elliptic Curves and compare the results with recent implementations in terms of speed and security.

Gröbner basis solutions of constrained interpolation problems

This paper extends the previous work of the authors on recursive Grobner basis techniques in coding theory, Pade approximation, partial realization, interpolation, and modelling discrete-time behaviours. We present a general algorithm, applicable to a wide range of constrained interpolation problems in coding theory and systems theory, including list decoding and M-Pade approximation.

Comparison of Two Algorithms for Decoding Alternant Codes

Abstract We compare the key equation solving algorithm introduced by Fitzpatrick to the Berlekamp-Massey algorithm. Our main result is that the two algorithms have the same computational complexity. It follows that in practice Fitzpatricks algorithm improves on Berlekamp-Massey since it uses less storage and has a simpler control structure. We also give an improved version of Fitzpatricks algorithm and a new simplified proof of the central inductive step in the argument.