Linda Logan-Henfrey

Cloning of a cDNA encoding bovine erythropoietin and analysis of its transcription in selected tissues

A bovine cDNA encoding erythropoietin (Epo) was isolated by polymerase chain reaction (PCR) amplification and screening of a bovine kidney cDNA library. The sequenced cDNA has a length of 1312 bp and an open reading frame that encodes a predicted 192-amino-acid (aa) protein, including a putative signal sequence of 25 aa. A mature protein of 167 aa (18.4 kDa) results upon cleavage of the putative signal peptide. The deduced bovine mature Epo peptide exhibits 96, 88, 83, 82 and 79% sequence identity to that of sheep, swine, human, monkey and rat, respectively. The expression of the bovine Epo gene in tissues from a severely anemic calf, bovine fetus and a healthy steer was analysed by a competitive RT-PCR method. In kidneys of the severely anemic calf, Epo mRNA levels increased 60-fold relative to that from the kidneys of the healthy steer. Epo mRNA levels were threefold higher in the liver of the bovine fetus than that in its kidneys. Low levels of Epo transcripts were detected in RNA from spleen of the severely anemic calf and the bovine fetus. No Epo transcripts were detectable in spleen from the healthy steer.

The effect of Trypanosoma brucei brucei infection on rabbit plasma iron and zinc concentrations

Changes in plasma iron and zinc concentration were studied in rabbits following a needle challenge with Trypanosoma brucei brucei clone ILTat 2.1. The infection resulted in a decrease of the concentration of both trace elements. Plasma iron concentrations decreased gradually and were decreased maximally to 52.3% of pre-infection levels on day 18 post-inoculation. Plasma zinc concentrations, on the other hand, decreased more rapidly and were decreased maximally to 27.4% of pre-infection levels on day 3 post-inoculation. The onset of these decreases coincided with the appearance of parasites in the peripheral blood. Furthermore, the magnitude of their decrease correlated closely with the level and duration of the parasitaemia. Other abnormal findings, namely, anaemia and periods of leucocytosis and leukopenia, were also observed. This study therefore demonstrates that depression in plasma iron and zinc concentrations is part of the acute phase response in rabbits infected with this clone of T. b. brucei.

Mitigation of Bioterrorist Threats in the 21st Century

Abstract: There is a raising level of awareness and concern that agriculture and food supplies might serve as targets for bioterrorists. To minimize such threats a number of new initiates are urgently needed: 1. Greater levels of financial commitment from federal, state, and international organizations for research on highly infectious diseases and for emergency response infrastructure; 2. Well‐orchestrated emergency response plans based on inter‐agency, inter‐departmental and stakeholder working groups; 3. Teams prepared for risk assessment and risk communication; 4. Modern systems of animal identification and accurate trace‐back for animal movement; 5. Increased biosecurity in intensive production operations; 6. accurate intelligence as to what pathogens pose the highest risks for economic and social impact; 7. Establishment of new international animal and plant disease research networks and partnerships; 8. Strengthen international disease surveillance networks for early detection and intervention; 9. New generations of rapid diagnostic tests for pathogen detection that are practical for field and diagnostic laboratories; 10. Increased level of commitment to pathogen genomics research for molecular epidemiology and vaccine development; 11. New chemical and immunological intervention strategies to prevent or control disease outbreaks; 12. Increased level of training on exotic and emerging animal diseases in basic veterinary education and through continuing education for veterinarians, state and federal field personnel and laboratory diagnosticians.

Expression of antigens on haemopoietic progenitor cells in bovine bone marrow

We analysed the surface phenotype of bovine bone marrow erythroid and myeloid progenitor cells with monoclonal antibodies (mAbs) from the Second Workshop. For the antibodies tested, no difference could be observed in burst-forming unit (erythroid) and colony-forming unit (erythroid) both are positive for BoCD44, BoWC9, MHC Class I, transferrin receptor and the p150/158 antigen detected by BT3/8.12, but neither express BoCD11a, BoCD45, BoWC5 or the antigen recognized by mAb Bo116. The myeloid progenitor cells, colony-forming unit (granulocyte/macrophage), can be discriminated from the erythroid progenitors by the absence of a transferrin receptor and the expression of BoCD11a and BoWC5 antigens. By selecting the right panel of mAbs, it should now be possible to enrich bone marrow cells for erythroid and/or myeloid progenitor cells.