Sequencing the genome of the Atlantic salmon (<Emphasis Type="Italic">Salmo salar</Emphasis>)

The International Collaboration to Sequence the Atlantic Salmon Genome (ICSASG) will produce a genome sequence that identifies and physically maps all genes in the Atlantic salmon genome and acts as a reference sequence for other salmonids.     

Ecoimmunity in Darwin's Finches: Invasive Parasites Trigger Acquired Immunity in the Medium Ground Finch (Geospiza fortis)

Background

Invasive parasites are a major threat to island populations of animals. Darwin''s finches of the Galápagos Islands are under attack by introduced pox virus (Poxvirus avium) and nest flies (Philornis downsi). We developed assays for parasite-specific antibody responses in Darwin''s finches (Geospiza fortis), to test for relationships between adaptive immune responses to novel parasites and spatial-temporal variation in the occurrence of parasite pressure among G. fortis populations.

Methodology/Principal Findings

We developed enzyme-linked immunosorbent assays (ELISAs) for the presence of antibodies in the serum of Darwin''s finches specific to pox virus or Philornis proteins. We compared antibody levels between bird populations with and without evidence of pox infection (visible lesions), and among birds sampled before nesting (prior to nest-fly exposure) versus during nesting (with fly exposure). Birds from the Pox-positive population had higher levels of pox-binding antibodies. Philornis-binding antibody levels were higher in birds sampled during nesting. Female birds, which occupy the nest, had higher Philornis-binding antibody levels than males. The study was limited by an inability to confirm pox exposure independent of obvious lesions. However, the lasting effects of pox infection (e.g., scarring and lost digits) were expected to be reliable indicators of prior pox infection.

Conclusions/Significance

This is the first demonstration, to our knowledge, of parasite-specific antibody responses to multiple classes of parasites in a wild population of birds. Darwin''s finches initiated acquired immune responses to novel parasites. Our study has vital implications for invasion biology and ecological immunology. The adaptive immune response of Darwin''s finches may help combat the negative effects of parasitism. Alternatively, the physiological cost of mounting such a response could outweigh any benefits, accelerating population decline. Tests of the fitness implications of parasite-specific immune responses in Darwin''s finches are urgently needed.     

Partial 28S rDNA sequences and the antiquity of hydrothermal vent endemic gastropods

A molecular phylogenetic investigation of the hypothesized antiquity of the hydrothermal vent endemic Neomphalina (Mollusca; Gastropoda) is reported. Sequences of two domains of the gene encoding for 28S ribosomal RNA were acquired for 3 outgroup and 32 gastropod genera. Use of the likelihood ratio test indicated complex substitution patterns for these domains and taxa, corresponding to a general time-reversible model with among-site rate variation. Phylogenetic analyses were performed using this model under maximum likelihood criteria. The data lacked resolution of gastropod radiations of the Paleozoic and all three of the outgroup sequences were randomized relative to the ingroup. Acceleration of evolutionary rates had additionally randomized the sequences of the Patellogastropoda relative to the other Gastropoda. The data resolved radiations of the Mesozoic and supported monophyly of the sampled Neritopsina, Vetigastropoda, Neomphalina, Caenogastropoda (including Campanile and the Architaenioglossa), and Heterobranchia (Valvata + Euthyneura), although several results were not significantly different from nonmonophyletic alternatives. Mesozoic origins of the hydrothermal vent endemic Neomphalina are preliminarily supported and implications for the hydrothermal vent refugia hypothesis discussed. Issues related to phylogenetic resolution of the Gastropoda are additionally discussed.     

The CYP inhibitor 1-aminobenzotriazole does not prevent oxidative stress associated with alcohol-induced liver injury in rats and mice

Cytochrome P450 (CYP) 2E1 is induced by ethanol and is postulated to be a source of reactive oxygen species during alcoholic liver disease. However, there was no difference in liver pathology and radical formation between wild-type and CYP2E1 knockout mice fed ethanol. Other CYP isoforms may contribute these effects if CYP2E1 is inhibited or absent. The purpose of this study was, therefore, to determine if blocking most of the P450 isoforms with 1-aminobenzotriazole (ABT; 100 mg/kg i.g.), has any effect on liver damage and oxidative stress due to alcohol in rats and mice. Male C57BL/6 mice and Wistar rats were fed either high-fat control or ethanol-containing enteral diet for 4 weeks. ABT had a significant inhibitory effect on many P450 isoforms independent of concomitant alcohol administration. However, ABT did not protect against liver damage due to alcohol in either species. Indices of oxidative stress and inflammation were also similar in livers from vehicle-treated and ABT-treated animals fed ethanol. In summary, suppression of P450 activity with ABT had no apparent effect on oxidative stress caused by alcohol in both rats and mice. These data support the hypothesis that oxidative stress and liver damage can occur independently of CYP activities in both rats and mice during early alcohol-induced liver injury.     

Protoplasts in organelle research: Transfer and transformation of plastids

Protoplasts, because they lack the wall of a typical higher plant cell, offer unique opportunities for experimental manipulation of their organellar constituents. Here, we report on modification of the organellar content of Nicotiana tabacum protoplasts by microfusion-induced transfer of defined numbers of chloroplasts into albino recipient cells. A single chloroplast is found to be sufficient for establishing a new plastid population in the progeny of the recipient cell. The frequency of green or variegated regenerants is shown to be genotype dependent. It can be drastically increased by using selection pressure for the transferred organelle. We also report on transient expression of plastid specific reporter gene constructs in plastids after PEG-mediated direct gene transfer into Nicotiana plumbaginifolia protoplasts. The expression is shown to be localized in the plastids by determining gene expression in isolated chloroplasts under conditins which completely remove cytoplasmic enzyme activity derived from a nuclear reporter gene construct. These data demonstrate for the first time that functional DNA, introduced into the cytoplasm by direct gene transfer, enters the organellar compartment and is expressed.     

Tissue culture of wild-type, interspecific genome/plastome hybrids and plastome mutants of evening primrose (Oenothera): controlled morphogenesis and transformation

A favourable combination of genetic features in the genus Oenothera offers access to fundamental biological aspects that are not readily approached with other materials. We have developed protocols for cell and tissue culture as well as for transformation, in order to establish the basis for a comprehensive cell and molecular biology of Euoenothera species, their genome/plastome hybrids and plastome mutants. Regeneration of plants from excised seedling parts (roots, hypocotyl, cotyledons, shoot tips) and leaf explants was optimal on NT medium containing 1 mg ⋅ l^–1 6-benzylaminopurine and 3 mg ⋅ l^–1 α-naphtalene acetic acid. This medium also proved to be efficient in the propagation of various wild-type genotypes, interspecific hybrids and plastome mutants. Using Ti-based approaches we also succeeded in generating transgenic Oenothera plants with relatively high efficiency. Received: 17 February 1997 / Revision received: 16 April 1997 / Accepted: 20 April 1997     

Rapid and sensitive GC/MS characterization of glycolipid released Galalpha1,3Gal-terminated oligosaccharides from small organ specimens of a single pig

Pig to human xenotransplantation is considered a possible solution to the prevailing chronic lack of human donor organs for allotransplantation. The Galalpha1,3Gal determinant is the major porcine xenogeneic epitope causing hyperacute rejection following human antibody binding and complement activation. In order to characterize the tissue distribution of Galalpha1,3Gal-containing and blood group- type glycosphingolipids in pig, acid and nonacid glycosphingolipids were isolated from the kidney, small intestine, spleen, salivary gland, liver, and heart of a single pig obtained from a semi-inbred strain homozygous at the SLA locus. Glycolipids were analyzed by thin-layer immunostaining using monoclonal antibodies, and following ceramide glycanase cleavage as permethylated oligosaccharides by gas chromatography, gas chromatography-mass spectrometry, and matrix- assisted laser desorption/ionization mass spectrometry. The kidney contained large amounts of Galalpha1,3Gal-containing penta- and hexasaccharides having carbohydrate sequences consistent with the Galalpha1,3nLc4and Galalpha1,3Lexstructures, respectively. The former structure was tentatively identified in all organs by GC/MS. The presence of extended Galalpha1,3Gal-terminated structures in the kidney and heart was suggested by antibody binding, and GC/MS indicated the presence of a Galalpha1,3nLc6structure in the heart. The kidney, spleen, and heart contained blood group H pentaglycosylceramides based on type 1 (H-5-1) and type 2 (H-5-2) chains, and H hexaglycosylceramides based on the type 4 chain (H-6-4). In the intestine H-5-1 and H-6-4 were expressed, in the salivary gland H-5-1 and H-5-2, whereas only the H-5-1 structure was identified in the liver. Blood group A structures were identified in the salivary gland and the heart by antibody binding and GC/MS, indicating an organ- specific expression of blood group AH antigens in the pig.      

Subcellular location of lincomycin resistance in Nicotiana mutants

Summary Lincomycin-resistant Nicotiana plumbaginifolia plastid mutants were considered also to carry mitochondrial mutations on the basis of their ability to grow in the dark under selective conditions. To clarify the role of mitochondria, individual protoplasts of the green, lincomycin-resistant N. plumbaginifolia mutant LR400 were microfused with protoplasts of the N. tabacum plastid albino line 92V37, which possesses N. undulata cytoplasm. The production of lincomycin-resistant albino cybrid lines, with N. undulata plastids and recombinant mitochondria, strongly indicated a determining role for mitochondria in the lincomycin resistance. Sequence analysis of the region encompassing putative mutation sites in the 26S rRNA genes from the LR400 and several other lincomycin-resistant N. plumbaginifolia mutants revelaed, however, no differences from the wild-type sequence. As an alternative source of the resistance of the fusion products, the N. tabacum fusion partner was also taken into account. Surprisingly, a natural lincomycin resistance of tobacco was detected, which was inherited as a dominant nuclear trait. This result compromises the interpretation of the fusion data suggested above. Thus, to answer the original question definitively, the mutant LR400 was crossed as a female parent with a N. plumbaginifolia line carrying streptomycin-resistant N. tabacum plastids. Calli were then induced from the seedlings. Occasional paternal plastid transmissions were selected as streptomycin-resistant calli on selective medium. These cell lines were shown by restriction enzyme analysis to contain paternal plastids and maternal mitochondria. They were tested for greening and growing ability in the presence of lincomycin. These resistance traits proved to be genetically linked and exclusively located in the plastids.EMBL accession number X68710