Studies of the antibody heterogeneity in carp (Cyprinus carpio L.). I. Electrophoretic and isoelectric spectra of anti-DNP-antibodies]

Carp IgM as well as carp anti-DNP-antibodies migrate electrophoretically very well as a diffuse band into polyacrylamide gel of large pore size. The isoelectric spectra of the carp anti-DNP-antibodies are heterogeneous and show bands in the pI-range of 4.0 to 6.4. The activity of focused anti-DNP-antibodies could be demonstrated in the pI range between 5.4 to 6.4 even in high antibody dilutions. The investigated structural heterogeneity of the anti-DNP-antibodies of carp is a further proof for the phylogenetically early onset of a large antibody heterogeneity of lower vertebrates.     

Structural and immunochemical studies of carp (Cyprinus carpio L.) immunoglobulin. V. Tryptic fragments of carp (Cyprinus carpio L.) immunoglobulin M]

Carp IgM, isolated from normal serum is more sensitive to trypsinization compared to a human myeloma protein IgMGo. Under the same conditions (treatment with trypsin at 56 degrees C for 30 min) carp IgM was degraded to small, mostly dialysable peptides to a larger extent than IgMGo. In both cases the fragmentation resulted in immunoelectrophoretically pure Fab mu and Fc mu fragments. The Fab mu fragments of human IgM (yield: 20% of used IgM material) had a molecular weight of 54,000, the Fc mu fragments (yield: 30%) were a heterogenous mixture as far as molecular sizes concerned with values of about 300,000. For the corresponding fragments of carp IgM we could analyze a molecular weight of about 43,000 for Fab mu (yield: 8%) and for Fc mu (yield 10%) three fractions of 160,000, 130,000 and 90,000. The reductive subunits of Fc mu fragments showed different molecular weights: 39,000 for IgMGo and 45,000 for carp IgM. The anti-fragment antisera prepared in rabbits were monospecific as demonstrated by immunodiffusion.     

Evolution of arthropod hemocyanins and insect storage proteins (hexamerins)

Crustacean and cheliceratan hemocyanins (oxygen-transport proteins) and insect hexamerins (storage proteins) are homologous gene products, although the latter do not bind oxygen and do not possess the copper- binding histidines present in the hemocyanins. An alignment of 19 amino acid sequences of hemocyanin subunits and insect hexamerins was made, based on the conservation of elements of secondary structure observed in X-ray structures of two hemocyanin subunits. The alignment was analyzed using parsimony and neighbor-joining methods. Results provide strong indications for grouping together the sequences of the 2 crustacean hemocyanin subunits, the 5 cheliceratan hemocyanin subunits, and the 12 insect hexamerins. Within the insect clade, four methionine- rich proteins, four arylphorins, and two juvenile hormone-suppressible proteins from Lepidoptera, as well as two dipteran proteins, form four separate groups. In the absence of an outgroup sequence, it is not possible to present information about the ancestral state from which these proteins are derived. Although this family of proteins clearly consists of homologous gene products, there remain striking differences in gene organization and site of biosynthesis of the proteins within the cell. Because studies on 18S and 12S rRNA sequences indicate a rather close relationship between insects and crustaceans, we propose that hemocyanin is the ancestral arthropod protein and that insect hexamerins lost their copper-binding capability after divergence of the insects from the crustaceans.      

Phoma glomerata, a potential new threat to Italian inland waters

Non-indigenous crayfish species, carrier of the oomycete Aphanomyces astaci, are the most important threats to European crayfish species. However, other ectoparasite species have been reported to be the pathogen of aquatic organisms. As little is known about other potential pathogens carried by the red swamp crayfish Procambarus clarkii, a total of 86 individuals of this species was collected in Lake Trasimeno from June 2007 to 2008. Phoma glomerata, never recorded in Italy, colonised more than 65% of the captured crayfish. No significant differences in prevalence were recorded between sexes, among life stages and between soft- and hard-shelled crayfish. This Coelomycetes is the causal agent of many diseases in plants, animals and humans. These results may contribute to a better understanding of the implications of epibiontic microfungi on the invasive crayfish P. clarkii, for both ecological and sanitary purposes.     

MicroRNA regulation of Cbx7 mediates a switch of Polycomb orthologs during ESC differentiation

The Polycomb Group (PcG) of chromatin modifiers regulates pluripotency and differentiation. Mammalian genomes encode multiple homologs of the Polycomb repressive complex 1 (PRC1) components, including five orthologs of the Drosophila Polycomb protein (Cbx2, Cbx4, Cbx6, Cbx7, and Cbx8). We have identified Cbx7 as the primary Polycomb ortholog of PRC1 complexes in embryonic stem cells (ESCs). The expression of Cbx7 is downregulated during ESC differentiation, preceding the upregulation of Cbx2, Cbx4, and Cbx8, which are directly repressed by Cbx7. Ectopic expression of Cbx7 inhibits differentiation and X chromosome inactivation and enhances ESC self-renewal. Conversely, Cbx7 knockdown induces differentiation and derepresses lineage-specific markers. In a functional screen, we identified the miR-125 and miR-181 families as regulators of Cbx7 that are induced during ESC differentiation. Ectopic expression of these miRNAs accelerates ESC differentiation via regulation of Cbx7. These observations establish a critical role for Cbx7 and its regulatory miRNAs in determining pluripotency.     

Entomopathogenic Nematodes Are Not an Alternative to Fenamiphos for Management of Plant-Parasitic Nematodes on Golf Courses in Florida

With the cancellation of fenamiphos in the near future, alternative nematode management tactics for plant-parasitic nematodes (PPN) on golf courses need to be identified. The use of entomopathogenic nematodes (EPN) has been suggested as one possible alternative. This paper presents the results of 10 experiments evaluating the efficacy of EPN at managing PPN on turfgrasses and improving turf performance. These experiments were conducted at various locations throughout Florida over the course of a decade. In different experiments, different EPN species were tested against different species of PPN. Separate experiments evaluated multiple rates and applications of EPN, compared different EPN species, and compared single EPN species against multiple species of PPN. In a few trials, EPN were associated with reductions in certain plant-parasite species, but in other trials were associated with increases. In most trials, EPN had no effect on plant parasites. Because EPN were so inconsistent in their results, we conclude that EPN are not acceptable alternatives to fenamiphos by most turf managers in Florida at this time.