Newer drug treatment in dermatology

In a study of 58 patients with various diseases of muscle or of the neuromuscular system, the serum activity of various enzymes was measured. Abnormal elevation of serum activities of aldolase, lactic dehydrogenase and, to a lesser extent, glutamic-oxalacetic transaminase and phosphohexose isomerase, was an almost constant feature in patients with progressive muscular dystrophy. These elevations were very frequent in dermatomyositis, common in acute cerebral vascular accidents, and rarely seen in other neurological disorders. Abnormal serum activity of iso-citric dehydrogenase was not observed in the course of the present study. Supplementary protein feeding of patients with muscular dystrophy had no effect on serum enzyme activity, no consistent effect on urinary creatine excretion and no effect on the strength of the patient or the course of the disease. Dystrophic muscles from a dystrophic strain of mice showed a decrease in activity of lactic dehydrogenase and aldolase below that of control muscle and an increase of iso-citric dehydrogenase activity. These findings, taken with the differences in serum activities of lactic dehydrogenase, aldolase and isocitric dehydrogenase in the dystrophic animals, support the conclusion that dystrophic animals handle these soluble enzymes in quite different ways.     

The Apical Organization and Phyllotaxis of the Oil Palm

The oil palm apex is described, together with investigationsof its phyllotaxis as revealed by apical dissection and measurementson mature stems and axillary structures. The rate of growthof the apex is remarkably low, being correlated with both plastochroneand phyllotaxis height. This is discussed in relation to therates of dry-matter production determined for adult palms. Thephyllotaxis as determined in the apex is remarkably constant,irrespective of extremes of age and habitat, and the same patternis found almost unchanged in the leaf bases on mature stemsgrowing under plantation conditions. Modification of the characteristicphyllotaxis height occurs due to internal factors resultingin the basal swelling of the palm stem and the different phyllotaxisof branching systems, both vegetative and reproductive, andalso due to external factors which cause constrictions in thestem. These modifications result from different rates of longitudinaland radial growth during development, and cause considerablechange in phyllotaxis.     

Reproductive biology of the rare and endangered Banksia brownii Baxter ex R. Br. (Proteaceae)

Abstract Banksia brownii is an endangered species, now limited to ～ 15 disjunct populations in southwestern Western Australia. Data on flowering phenology, plant size, fruit set, pollination and the mating system were gathered for two of these populations between March and October 1993. Flowering for both populations followed a similar pattern, with open flowers first evident in April, and the number of inflorescences with open flowers peaking in June. At both locations, trees differed considerably with respect to their size, the total number of inflorescences produced and the length of their flowering season. Fruiting success was typically low, with approximately half of all inflorescences failing to develop into infructescences. Only 1. 8% of the flowers originally present on inflorescences developed into follicles. The distribution of follicles along each infructescence was non-random, with most forming in the middle third of the infructescence for reasons relating to nutrient supply and pollinator behaviour. More flowers opened during the day than at night, although pollen was lost from individual flowers during both periods. Honeyeaters such as Phylidonyris novaehollandiae were common at the two study sites, and often carried large loads of B. brownii pollen. Though less frequently caught, the nocturnal mammals Rattus fuscipes and Tarsipes rostratus also bore substantial amounts of pollen. Most inflorescences from which these mammals and birds were excluded remained barren. Fruiting success was further reduced when invertebrates such as Apis mellifera were also prevented from visiting inflorescences. The ability of B. brownii to set at least some fruit in the absence of biotic poli-nators indicates that the species is partially self-compatible. Honeyeaters foraged preferentially at inflorescences with one to two thirds of their flowers open, probing mainly along the ‘advancing front’ of open flowers. These animals moved more frequently between inflorescences on the same plant than between those on different plants, and were often recaptured in the same locations. Mammals also appeared to be sedentary. Both B. brownii populations had mixed mating systems, with genetically determined outcrossing rates of ～0.7. The unusually high level of selfing in each population is presumably a reflection of the species’ self-compatibility and the foraging behaviour of its pollinators.     

Metabolic control analysis of plant metabolism

Metabolic control analysis and its major coefficients are introduced. The importance of measuring both elasticity and concentration-control coefficients as well as flux-control coefficients is stressed. The conditions that need to be met before control analysis can be applied experimentally are emphasized. It is argued that successful application of this approach requires methods for the measurement of flux, maximum catalytic activities of enzymes and substrate contents. The measurement of flux by consumption of substrate, production of product, and the distribution of isotope after metabolism of labelled substrates is discussed. The need to ensure that measurements of enzymes and substrates are reliable and authenticated is stressed. Particular emphasis is placed on the ease with which such measurements can be invalidated in plant tissues, and ways for countering these difficulties are discussed.