Publications (48) View all
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Article: Microarray-detected changes in gene expression in gills of green crabs (Carcinus maenas) upon dilution of environmental salinity.
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ABSTRACT: The interaction between environmental salinity and gene expression was studied in gills of the euryhaline green shore crab Carcinus maenas. A 4462-feature oligonucleotide microarray was used to analyze changes in transcript abundance in posterior ion-transporting gills at 8 time periods following transfer of animals from 32 to 10 or 15 ppt salinity. Transcripts encoding Na(+)/K(+)-ATPase α-subunit and cytoplasmic carbonic anhydrase were upregulated with significant changes between 6 and 24h post-transfer. Other transport proteins showing similar transcriptional upregulation were an organic cation transporter, a sodium/glucose cotransporter, an endomembrane protein associated with regulating plasma membrane protein composition, and a voltage-gated calcium channel. Transport proteins showing little transcriptional response included Na(+)/H(+) exchanger, Na(+)/K(+)/2Cl(-) cotransporter, and V-type H(+)-ATPase B subunit, all of which have been implicated in osmoregulatory ion transport across crustacean gill. Interestingly, there was little affect of salinity dilution on transcriptional expression of stress proteins, suggesting that salinity acclimation is part of normal physiology for C. maenas. Expression of transcripts encoding a variety of mitochondrial proteins was significantly upregulated between 4 days and 7 days post-transfer, consistent with the proliferation of mitochondria-rich cells previously observed at this time.Comparative Biochemistry and Physiology Part D Genomics and Proteomics 12/2010; 6(2):115-25. · 1.72 Impact Factor -
Article: Recent advances in crustacean genomics.
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ABSTRACT: Crustaceans are a diverse and ancient group of arthropods that have long been studied as interesting model systems in biology, especially for understanding animal evolution and physiology and for environmentally relevant studies. Like many model systems, advances in DNA-sequencing methodologies have led to a large amount of genomics-related projects. The purpose of this article is to highlight the genome projects and functional genomics (transcriptomics) projects that are currently underway in crustacean biology. Specifically, we have surveyed the amount of publicly available DNA sequence data (both genomic and EST data) across all crustacean taxa for which a significant number of DNA sequences have been generated. Several ongoing projects are presented including the ecology of invasive species, thermal physiology, ion and water balance, ecology and evolutionary biology, and developmental biology.Integrative and Comparative Biology 12/2008; 48(6):852-868. · 2.45 Impact Factor -
Article: Hemocyanins and the immune response: defense against the dark arts.
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ABSTRACT: The innate immune response is a conserved trait shared by invertebrates and vertebrates. In crustaceans, circulating hemocytes play significant roles in the immune response, including the release of prophenoloxidases. Activated phenoloxidase (tyrosinase) participates in encapsulation and melanization of foreign organisms as well as sclerotization of the new exoskeleton after wound-repair or molting. Hemocyanin functions as a phenoloxidase under certain conditions and thus also participates in the immune response and molting. The relative contributions of hemocyte phenoloxidase and hemocyanin in the physiological ratio at which they occur in hemolymph have been investigated in the crab Cancer magister. Differences in activity, substrate affinity, and catalytic ability between the two enzymes indicate that hemocytes are the predominant source of phenoloxidase activity in crabs. In contrast, hemocyanin is the primary source of phenoloxidase activity in isopods and chelicerates whose hemocytes show no phenoloxidase activity. Quantitative PCR studies on the distribution of prophenoloxidase mRNA in the tissues of Carcinus maenas showed little effect relative to salinity stress. Phylogenetic analysis of hemocyanin, phenoloxidase, and other members of this arthropod gene family are consistent with the possibility that a common ancestral molecule had both phenoloxidase and oxygen-binding capabilities.Integrative and Comparative Biology 10/2007; 47(4):662-5. · 2.45 Impact Factor -
Article: Crustacean hemocyanin gene family and microarray studies of expression change during eco-physiological stress.
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ABSTRACT: Proteins in the arthropod hemocyanin gene family are involved in major physiological processes, including aerobic respiration, the innate immune response, and molting. Members of this family, hemocyanin, cryptocyanin, and phenoloxidase, are multisubunit molecules that assemble into hexamers and higher aggregates. The hemocyanin hexamers show species-specific subunit heterogeneity. It is hypothesized that this subunit diversity is maintained as a mechanism of selection for functional diversity under changing developmental and environmental conditions. There is good evidence for a strong relationship between subunit composition and functional diversity in the hemocyanins. We have amplified, cloned, and sequenced the complete cDNAs of the 6 hemocyanin genes, 2 cryptocyanins, and 1 phenoloxidase of Cancer magister. Alignment of the amino acid sequences provides the first opportunity to assess in 1 species of brachyuran crustacean the similarities and differences among all the hemocyanin subunits and compare them with cryptocyanin and phenoloxidase. A phylogeny of sequences of crustacean members of the arthropod hemocyanin gene family is described. Construction of a cDNA library for C. magister microarray studies is in progress. The microarrays will be queried using transcriptional profiles from crabs sampled during developmental, molting, and physiological perturbations. The combination of genomics, proteomics, and gene-by-gene analyses will help us dissect how much a gene sequence in this hemocyanin family can vary while conserving function and which aspects of preservation of shape and structural flexibility are essential for functional stability. Integrating focused gene studies with global-expression profiling can eventually lead to the identification of functional networks at the level of the gene, the multisubunit molecule, and the whole organism.Integrative and Comparative Biology 12/2006; 46(6):991-9. · 2.45 Impact Factor -
Article: Functional and phylogenetic analyses of phenoloxidases from brachyuran (Cancer magister) and branchiopod (Artemia franciscana, Triops longicaudatus) crustaceans.
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ABSTRACT: Arthropod phenoloxidases catalyze the melanization and sclerotization of the new postmolt exoskeleton, and they function in the immune response. Hemocyanin, phylogenetically related to phenoloxidase, can function as a phenoloxidase under certain conditions. We investigated the relative contributions of hemocyte phenoloxidase and hemocyanin in the brachyuran crab Cancer magister, using the physiological ratio at which they occur in the hemolymph, and found that hemocyte phenoloxidase has higher activity. They both convert diphenols to o-quinones, but only the hemocyte phenoloxidase is able to catalyze the conversion of monophenols to diphenols. The quaternary structure of hemocyanin affects its reactivity as phenoloxidase. We suggest that prophenoloxidase is released from hemocytes and moves across epidermis into new exoskeleton during premolt and is activated in early postmolt. In addition to functional studies, we have determined the complete cDNA sequence of C. magister hemocyte prophenoloxidase and partial sequences from the branchiopods Artemia franciscana and Triops longicaudatus. We also sequenced C. magister cryptocyanin 2 and a hemocyanin from the amphipod Cyamus scammoni and used these and other members of the arthropod hemocyanin superfamily for phylogenetic analyses. The phylogenies presented here are consistent with the possibility that a common ancestral molecule had both phenoloxidase and reversible oxygen-binding capabilities.Biological Bulletin 03/2006; 210(1):38-50. · 1.70 Impact Factor
