42 research outputs found
Observations on the use of Anaplasma centrale for immunization of cattle against anaplasmosis in Zimbabwe
A total of 93 Bos taurus cattle was used in pen trials to compare vaccine stocks of Anaplasma centrale
from South Africa and Australia (which stock came from South Africa in 1934) in protecting against
three virulent field isolates from clinical Anaplasma marginale infections. In addition, field observations
were made on the use of a vaccine, prepared from the Australian stock, in over 9553 cattle of
mixed age and breeds on 16 co-operator farms and at one communal dip.
The results of the pen trials indicated that the two vaccine stocks were comparable and that neither
provided adequate protection against two of the three isolates of A. marginale. The field observations
indicated that the vaccine was highly infective and produced mild reactions in most recipient cattle,
and that users were generally satisfied with the vaccine.
These somewhat conflicting results are discussed in the context of observations in Australia and future
vaccination against anaplasmosis in Zimbabwe.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi.
Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Australian Centre for International Agricultural Research. Central Veterinary Laboratory, Zimbabwe. Queensland Department of Primary Industries, Australia.mn201
The splicing landscape is globally reprogrammed during male meiosis
Meiosis requires conserved transcriptional changes, but it is not known whether there is a corresponding set of RNA splicing switches. Here, we used RNAseq of mouse testis to identify changes associated with the progression from mitotic spermatogonia to meiotic spermatocytes. We identified ∼150 splicing switches, most of which affect conserved protein-coding exons. The expression of many key splicing regulators changed in the course of meiosis, including downregulation of polypyrimidine tract binding protein (PTBP1) and heterogeneous nuclear RNP A1, and upregulation of nPTB, Tra2β, muscleblind, CELF proteins, Sam68 and T-STAR. The sequences near the regulated exons were significantly enriched in target sites for PTB, Tra2β and STAR proteins. Reporter minigene experiments investigating representative exons in transfected cells showed that PTB binding sites were critical for splicing of a cassette exon in the Ralgps2 mRNA and a shift in alternative 5′ splice site usage in the Bptf mRNA. We speculate that nPTB might functionally replace PTBP1 during meiosis for some target exons, with changes in the expression of other splicing factors helping to establish meiotic splicing patterns. Our data suggest that there are substantial changes in the determinants and patterns of alternative splicing in the mitotic-to-meiotic transition of the germ cell cycle