High level of divergence of male-reproductive-tract proteins, between Drosophila melanogaster and its sibling species, D. simulans

We compared male-reproductive-tract polypeptides of Drosophila melanogaster and D. simulans by using two-dimensional gel electrophoresis. Approximately 64% of male-reproductive-tract polypeptides were identical between two randomly chosen isofemale lines from these two species, compared with 83% identity for third-instar imaginal wing-disc polypeptides. Qualitatively similar differences were found between reproductive tracts and imaginal discs when D. sechellia was compared with D. melanogaster and with D. simulans. When genic polymorphism was taken into account, approximately 10% of male- reproductive-tract polypeptides were apparently fixed for different alleles between D. melanogaster and D. simulans; this proportion is the same as that found for soluble enzymes by one-dimensional gel electrophoresis. Strikingly, approximately 20% of male-reproductive- tract polypeptides of either D. melanogaster or D. simulans had no detectable homologue in the other species. We propose that proteins of the Drosophila male reproductive tract may have diverged more extensively between species than have other types of proteins and that much of this divergence may involve large changes in levels of polypeptide expression.      

Glutathione-S-transferase,a possible drug-metabolizing enzyme,in Haemonchus contortus: Comparative activity of a cambendazole-resistant and a susceptible strain

Kawalek J. C., Rew R. S. and Heavner J. 1984. Glutathione-S-transferase, a possible drug-metabolizing enzyme in Haemonchus contortus: comparative activity of a cambendazole-resistant and a susceptible strain. International Journal for Parasitology14: 173–175. A drug metabolizing enzyme (DME), glutathione-S-transferase, was detected in homogenates of a cambendazole-susceptible and a cambendazole-resistant strain of Haemonchus contortus. The activity was 1.5–1.8 times higher in the resistant strain. DME activation is a possible mechanism for anthelmintic resistance in H. contortus.     

Effects of diamfenetide on metabolic and excretory functions of Fasciola hepatica in vitro

The effect of diamfenetide (DFT) on the time course of production of end-products of glucose metabolism, tissue ATP levels and NH3 production by adult Fasciola hepatica in vitro was determined. Products of glucose metabolism are increased between 6 and 24 hr incubation in 10(-4) M DFT. Tissue ATP levels and NH3 production are decreased during this time period. The observed metabolic effects of DFT are manifested at a much later time after drug exposure than previously described membrane-disruptive events indicating that metabolic effects of DFT on F. hepatica may be secondary to the initial effects on surface membranes.     

Effect of diamfenetide on experimental infections of Fasciola hepatica in lambs: anthelmintic and clinical investigations.

The activity of diamfenetide (N,N'-[oxybis(2,1-ethan diyloxy-4,1-phenylene)] bis acetamide) was studied in lambs experimentally inoculated with Fasciola hepatica. The drug was given orally at a dose level of 100 mg/kg either 1,3,5,7, or 9 weeks postinoculation. It was 100% effective 1, 3, and 5 weeks postinoculation, 73% effective 7 weeks postinoculation, and 57% effective 9 weeks postinoculation. Serum gamma-glutamyl transpeptidase activity remained normal in all lambs for 5 weeks after infection; it then began to increase in infected, untreated lambs at 6 weeks, and had increased 5- to 6-fold 9 weeks postinoculation in infected lambs. This enzyme activity was the most sensitive hematologic parameter used in this test to detect hepatobiliary damage by the parasite. The drug was well tolerated at the dose level used.     

Pre-induction priming of the uterine cervix with oral prostaglandin E2 and a placebo

A double blind study was undertaken to determine the effectiveness or oral prostaglandin E2 as a means of improving the pelvic score prior to induction of labour. 48 patients who were greater than 37 were gestation and who had Bishop scores of less than 6 entered the study. Ten tablets were given on an hourly regime. Of 25 patients in the prostaglandin group, 17 were considered successes (68.0%), whereas of 23 patients who received a placebo, 9 were successes (39.1%). No adverse effects were recorded. Prostaglandin E2 is therefore considered a safe and effective method for priming the unfavourable cervix prior to induction of labour.     

Monoclonal antibodies to rabbit liver cytochrome P-448

Cytochrome P-448 (mol wt 55,000 Daltons) from rabbit liver was purified to a specific content of 16.6 nmol/mg. Mice were immunised with this preparation, their spleens removed and dissociated lymphocytes hybridised with myeloma cells. Four monoclonal antibodies against cytochrome P-448 were raised and partially characterised. All four antibodies interacted with cytochrome P-448 in intact microsomal fractions and selectively immunoadsorbed cytochrome P-448 from solubilised microsomal preparations. One of the antibodies inhibited benzo[a] pyrene hydroxylase activity in a reconstituted system, one had no effect on activity and two increased activity. The possible applications of such antibodies are discussed.     

Drivers of <Emphasis Type="Italic">Bromus tectorum</Emphasis> Abundance in the Western North American Sagebrush Steppe

Bromus tectorum can transform ecosystems causing negative impacts on the ecological and economic values of sagebrush steppe of the western USA. Although our knowledge of the drivers of the regional distribution of B. tectorum has improved, we have yet to determine the relative importance of climate and local factors causing B. tectorum abundance and impact. To address this, we sampled 555 sites distributed geographically and ecologically throughout the sagebrush steppe. We recorded the canopy cover of B. tectorum, as well as local substrate and vegetation characteristics. Boosted regression tree modeling revealed that climate strongly limits the transformative ability of B. tectorum to a portion of the sagebrush steppe with dry summers (that is, July precipitation <10 mm and the driest annual quarter associated with a mean temperature >15°C) and low native grass canopy cover. This portion includes the Bonneville, Columbia, Lahontan, and lower Snake River basins. These areas are likely to require extreme efforts to reverse B. tectorum transformation. Our predictions, using future climate conditions, suggest that the transformative ability of B. tectorum may not expand geographically and could remain within the same climatically suitable basins. We found B. tectorum in locally disturbed areas within or adjacent to all of our sample sites, but not necessarily within sagebrush steppe vegetation. Conversion of the sagebrush steppe by B. tectorum, therefore, is more likely to occur outside the confines of its current climatically optimal region because of site-specific disturbances, including invasive species control efforts and sagebrush steppe mismanagement, rather than climate change.     

Production-based control of parasitic nematodes of cattle

Nematode parasite control in cattle is the goal of the parasitologist and the cattle producer. However, the language used to express the impact of that control has been a source of confusion between the two groups. Veterinary parasitologists speak in terms of reduction in worms or worm eggs, and cattle producers in terms of weight gain, milk production or calving rate. During the development of doramectin for cattle in temperate climates worldwide, the point came when we began to look for a different set of parameters to guide trial design and to communicate the results. In this paper, a series of published papers resulting from the yearling portion of this development programme are reviewed from the viewpoint of weight gain in relation to forage/feed availability. A pattern emerged that indicated that yearling cattle, when parasite control was effective (as indicated by egg counts) and forage was sufficient (as indicated by weather patterns), gained from 0.75 to 0.95 kg day(-1) in trials from the USA, Europe and Argentina. When parasite control or forage supply or both were insufficient, these rates of weight gain were significantly reduced. If more attention is spent on forage availability and weight-gain parameters when parasite-control programmes are designed, then researchers might communicate more meaningful information to producers on the value of parasite control.     

Growth of <Emphasis Type="Italic">Helicobacter pylori</Emphasis> in a long spiral form does not alter expression of immunodominant proteins

Background  

We have previously reported that altered culture conditions (a broth media with shaking) could induce a strain of Helicobacter pylori to assume a long spiral morphology resembling that described for Helicobacter heilmannii. The present study was initiated to determine if other strains of H. pylori could be induced to assume that morphology and if doing so would alter the expression of immunodominant proteins.     

Automation of mouse micronucleus genotoxicity assay by laser scanning cytometry

BACKGROUND: The evaluation of the safety of drugs and other chemicals is an important aspect of toxicology work. The mouse micronucleus assay is a standard in vivo genotoxicity assay. Chromosomal damage is an indicator of genotoxicity, which manifests in the formation of micronuclei in polychromatic erythrocytes from bone marrow and in peripheral blood erythrocytes. The assay is laborious to perform by manual counting. The laser scanning cytometer allows automated and rapid quantitation of cellular and subcellular fluorescence in monodisperse cell samples on a microscope slide. The object of this study was to evaluate the application of this new technology in the mouse micronucleus genotoxicity assay. Materials and Methods One hundred forty-four mice of various strains were dosed with combinations of carcinogens and antioxidants. Duplicate blood films were prepared 3 days later. One set of slides was stained with acridine orange, and the proportion of micronucleated erythrocytes was counted in 5,000 cells per slide. The duplicates were stained with propidium iodide (40 microg/ml). Five thousand cells per sample were examined using a laser scanning cytometer. The proportion of micronucleated erythrocytes was measured. RESULTS: A coefficient of correlation of 0.96 was found between the data from the two assays. The automation of the assay on the LSC produced a considerable time saving and efficiency gain. CONCLUSIONS: We conclude that with further development, laser scanning cytometry is likely to become the preferred modality for the performance of standard genotoxicity assays.