Lockhart, PJ, Beanland, TJ, Howe, CJ & Larkum, AW 1992, 'Sequence of Prochloron didemni atpBE and the inference of chloroplast origins.', Proceedings of the National Academy of Sciences, vol. 89, no. 7, pp. 2742-2746.
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The prochlorophytes, oxygenic photosynthetic prokaryotes containing chlorophylls a and b, have been put forward as descended from the organisms that gave rise to chloroplasts of green plants and algae by endosymbiosis, although this has always been controversial. To assess the phylogenetic position of the prochlorophyte Prochloron didemni, we have cloned and sequenced its atpBE genes. Phylogenetic inference under a range of models gives moderate to strong support for a cyanobacterial grouping rather than a chloroplast one. Possible systematic errors in this and previous analyses of prochlorophyte sequences are discussed.
O'Meara, TJ, Nesa, M, Raadsma, HW, Saville, DG & Sandeman, RM 1992, 'Variation in skin inflammatory responses between sheep bred for resistance or susceptibility to fleece rot and blowfly strike', Research in Veterinary Science, vol. 52, no. 2, pp. 205-210.
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Sheep which have been bred for resistance (R) or susceptibility (S) to fleece rot and blowfly strike, were tested for intradermal inflammatory responses to excretory and secretory products of Lucilia cuprina larvae. R rams and lambs gave significantly larger skin weals than S animals. In addition, R and S rams were infected with L cuprina first instar larvae and wound exudates were collected. In the first 12 hours of infection R rams released significantly more exudate protein at the wound site than S rams. Correlations suggested that exudate production was stimulated by both larval burden and inflammatory responses, however, in the R group the inflammatory correlation was positive while in the S group it was negative. The results imply that inflammatory responses may play a role in innate resistance to L cuprina. The difference in inflammatory responses suggests genetic differences between the flocks and therefore could show some potential as a trait for indirect selection for resistance to fleece rot and body strike.
RALPH, PJ, BURCHETT, MD & PULKOWNIK, A 1992, 'DISTRIBUTION OF EXTRACTABLE CARBOHYDRATE RESERVES WITHIN THE RHIZOME OF THE SEAGRASS POSIDONIA-AUSTRALIS HOOK F', AQUATIC BOTANY, vol. 42, no. 4, pp. 385-392.
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Rhizomes of Posidonia australis Hook. f., collected from Botany Bay on the eastern coast of Australia, were analysed for extractable carbohydrates. The concentration of extractable carbohydrate in the stelar tissue of the rhizome was significantly higher
Sandeman, RM, Chandler, RA, Collins, BJ & O'Meara, TJ 1992, 'Hypersensitivity responses and repeated infections with Lucilia cuprina, the sheep blowfly', International Journal for Parasitology, vol. 22, no. 8, pp. 1175-1177.
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Sheep repeatedly infected with L. cuprina at 2- but not 4-week intervals developed partial resistance to infection after five infections, as measured by larval recovery. However, resistance did not persist for more than three infections. Skin weal responses were measured after injection of larval products simultaneously with each infection. The only correlation between weal size and larval recoveries occurred at infection 1 and indicated a relationship between skin sensitivity and innate rather than acquired resistance. The results suggest that resistance to L. cuprina can develop after repeated infections but that it is short lived and requires frequent larval exposure. A role for hypersensitivity responses was not confirmed by the weal responses but was suggested by the size of wound developed per larva recovered.
Seaton, DS, O'meara, TJ, Chandler, RA & Sandeman, RM 1992, 'The sheep antibody response to repeated infection with Lucilia cuprina', International Journal for Parasitology, vol. 22, no. 8, pp. 1169-1174.
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The specific serum antibody responses of sheep exposed to 10 consecutive infections of L. cuprina have been analysed by enzyme-linked immuno-sorbent assay and immunoblotting using monoclonal antibodies specific for sheep immunoglobulin isotypes. Recognition of a number of larval excretory-secretory products by IgM antibodies appeared to be non-specific. IgG1 was the major antibody class stimulated by the infection protocol and marked increases in antibody to specific excretory-secretory antigens were observed. Three molecules of 35, 30 and 25 kDa were particularly recognized although the extent of recognition of these molecules varied considerably between individual sheep serum. A pooled serum composed of sera collected after five to seven infections significantly inhibited larval growth in in vitro cultures when compared to a sera pool consisting of sera collected both prior to infection and after infections 1 and 2. The degree of inhibition was greater when serum with high specific antibody titre was used.
