Selective inhibition of prostaglandin biosynthesis by gold salts and phenylbutazone

Gold salts and phenylbutazone selectively inhibit the synthesis of PGF_2α and PGE₂ respectively. Lowered production of one prostaglandin species is accompanied by an increased production of the other. Selective inhibition by these drugs was observed in the presence of adrenaline, reduced glutathione and copper sulphate under conditions when most anti-inflammatory compounds inhibited PGE₂ and PGF_2α syntheses equally. It is postulated that selective inhibitors may have a different mode of action in vivo and beneficial effects may be related to the endogenous ratio of PGE to PGF required for normal function.     

Structural rearrangements,including parallel inversions,within the chloroplast genome of Anemone and related genera

Chloroplast DNA cleavage sites for 10 restriction enzymes were mapped for 46 species representing all sections of Anemone, four closely related genera (Clematis, Pulsatilla, Hepatica, and Knowltonia), and three more distantly related outgroups (Caltha, Ranunculus, and Adonis). Comparison of the maps revealed that the chloroplast genomes of Anemone and related genera have sustained an unusual number and variety of rearrangements. A single inversion of a 42-kb segment was found in the large single-copy region of Adonis aestivalis. Two types of rearrangements were found in the chloroplast genome of Clematis, Anemone, Pulsatilla, Hepatica, and Knowltonia: An approximately 4-kb expansion of the inverted repeat and four inversions within the large single-copy region. These rearrangements support the monophyletic status of these genera, clearly separating them from Caltha, Ranunculus, and Adonis. Two further inversions were found in two Clematis species and three Anemone species. While appearing to support a monophyletic grouping for these taxa, these two inversions conflict with data from both chloroplast restriction sites and morphology and are better interpreted as having occurred twice independently. These are the first two documented cases of homoplastic inversions in chloroplast DNA. Finally, the second intron of the chloroplast rps12 gene was shown to have been lost in the common ancestor of the same three Anemone species that feature the two homoplastic inversions.     

Ecological cues, gestation length, and birth timing in African buffalo (Syncerus caffer)

We examined annual variation in the timing of conception andparturition in the African buffalo (Syncerus caffer) and thesynchrony of birth timing with resource cues, using 8 yearsof monthly birth, rainfall, and vegetation data, measured asNormalized Difference Vegetation Index (NDVI). Monthly birthshad the strongest significant correlations with NDVI and rainfalllevels 12 and 13 months in the past, respectively. In addition,the synchrony of current year births corresponds most stronglyto the synchrony of the previous year's NDVI distribution. Becausethe gestation period of buffalo has been estimated to be around11 months, these findings suggest that improved protein levels,occurring approximately a month after the first green flushof the wet season, are either a trigger for conception or conceptionhas evolved to be synchronous with correlated environmentalcues that ensure females enter a period of peak body conditionaround the time of conception and/or parturition. With a gestationperiod of approximately 340 days, parturition occurs to takeadvantage of the period when forage has its highest proteincontent. A comparative analysis of gestation periods withinthe subfamily Bovinae indicates that African buffalo have aprotracted gestation for their body size, which we suggest isan adaptation to their seasonal environment. We also found thatinterannual variation in the birth distribution suggests a degreeof plasticity in the date of conception, and variation in thenumber of calves born each year suggest further synchrony ata timescale longer than a single year.