Effect of ploidy on scale-cover pattern in linear ornamental (koi) common carp Cyprinus carpio.

The effect of ploidy on scale-cover pattern in linear ornamental (koi) common carp Cyprinus carpio was investigated. To obtain diploid and triploid linear fish, eggs taken from a leather C. carpio female (genotype ssNn) and sperm taken from a scaled C. carpio male (genotype SSnn) were used for the production of control (no shock) and heat-shocked progeny. In heat-shocked progeny, the 2 min heat shock (40° C) was applied 6 min after insemination. Diploid linear fish (genotype SsNn) demonstrated a scale-cover pattern typical for this category with one even row of scales along lateral line and few scales located near operculum and at bases of fins. The majority (97%) of triploid linear fish (genotype SssNnn) exhibited non-typical scale patterns which were characterized by the appearance of additional scales on the body. The extent of additional scales in triploid linear fish was variable; some fish had large scales, which covered almost the entire body. Apparently, the observed difference in scale-cover pattern between triploid and diploid linear fish was caused by different phenotypic expression of gene N/n. Due to incomplete dominance of allele N, triploids Nnn demonstrate less profound reduction of scale cover compared with diploids Nn.

Distinct physiological states of Plasmodium falciparum in malaria-infected patients.

Infection with the malaria parasite Plasmodium falciparum leads to widely different clinical conditions in children, ranging from mild flu-like symptoms to coma and death. Despite the immense medical implications, the genetic and molecular basis of this diversity remains largely unknown. Studies of in vitro gene expression have found few transcriptional differences between different parasite strains. Here we present a large study of in vivo expression profiles of parasites derived directly from blood samples from infected patients. The in vivo expression profiles define three distinct transcriptional states. The biological basis of these states can be interpreted by comparison with an extensive compendium of expression data in the yeast Saccharomyces cerevisiae. The three states in vivo closely resemble, first, active growth based on glycolytic metabolism, second, a starvation response accompanied by metabolism of alternative carbon sources, and third, an environmental stress response. The glycolytic state is highly similar to the known profile of the ring stage in vitro, but the other states have not been observed in vitro. The results reveal a previously unknown physiological diversity in the in vivo biology of the malaria parasite, in particular evidence for a functional mitochondrion in the asexual-stage parasite, and indicate in vivo and in vitro studies to determine how this variation may affect disease manifestations and treatment.

Enzyme treatment of Trypanosoma danilewskyi (Laveran and Mesnil) increases its susceptibility to lysis by the alternative complement pathway of goldfish, Carassius auratus (L.).

This study examined whether in vitro-cultured Trypanosoma danilewskyi were susceptible to lysis in the presence or absence of anti-parasite antibodies and complement. Cultured trypanosomes were resistant to lysis by either immune or non-immune goldfish serum. However, trypanosomes treated with the proteolytic enzyme trypsin, which destroys surface proteins of the parasites, became susceptible to lysis when exposed to either immune or non-immune goldfish serum. The lysis by goldfish serum was dependent on the presence of heat-labile factors and occurred at 4 and 20 degrees C. The lysis was also dependent on the presence of Mg(2+) ions but not Ca(2+) ions. Furthermore, treatment of the parasites with different sialidases did not enhance their susceptibility to lysis by goldfish serum. Trypsinized parasites regained resistance to lysis after at least 6-h cultivation in the absence of trypsin and the restoration of full resistance was observed after 24-h cultivation. The resistance to lysis was abrogated when the protein synthesis inhibitor, puromycin, was added to the cultures. These results suggest that trypsinized trypanosomes were susceptible to lysis by goldfish complement (alternative pathway) and that protective surface proteins of the parasite were required for the resistance of normal trypanosomes to lysis.

Immunization of goldfish with excretory/secretory molecules of Trypanosoma danilewskyi confers protection against infection.

Trypanosoma danilewskyi is a protozoan that lives in blood and other tissues of fish. In the aquaculture industry, economic losses may be substantial, since the prevalence of infection may approach 100% and the parasite may cause significant mortality in farmed carp. Most of the surviving fish acquire resistance after elimination of the primary infection. In this study, we examined whether protection against infection could be induced in naïve goldfish immunized with excretory-secretory (ES) products of the parasite. The ES extracts were administered in conjunction with Freund's complete or incomplete adjuvant (FCA and FIA, respectively). Parameters used to assess the efficacy of immunization after challenge infection, included prevalence of infection, abundance of parasites, and presence of parasite-specific antibodies. Intraperitoneal inoculation of ES products in FCA conferred protection against T. danilewskyi infection (P<0.05). Administration of ES products (with or without FIA) conferred insignificant levels of protection. In an attempt to identify the immunogenic ES molecules, we assessed whether anti-parasite antibodies present in the serum collected from experimentally infected fish or rabbits immunized with ES recognized parasite ES antigens. An immunoblot using rabbit anti-parasite antibody revealed a recognition profile of molecules (two antigens of approximately 102-104 and 70-72kDa) similar to that of immune goldfish serum. While the antigens that confer protection need further molecular characterization, our results suggest that the administration of ES products may allow for the design of control strategies for T. danilewskyi.

Sensitivity of radiometric measurements of the atmospheric CO2 column from space.

Anthropogenic emissions of CO2 over the past century has altered significantly the global carbon cycle. Our understanding of the long-term climatic effects of these emissions would be improved greatly by satellite-based remote sounding of CO2. We provide an initial analysis of a simple satellite-based filter radiometer tuned to the spectral region around 6300 cm(-1) (approximately 1.6 microm) to measure the atmospheric column of CO2 from space. We find that such an instrument has potential and that the sensitivity would be limited by our knowledge of the tropospheric temperature and water-vapor profiles.