Enzyme formation in higher plant tissue

Summary Ageing slices of artichoke tuber or carrot root produced a substance, characterised as a protein, which when added to freshly cut slices inhibited invertase development. For maximum effect, it was necessary to expose the tissue to inhibitor immediately on excision, and this resulted in a slower rate of enzyme production and a lower final level. We suggest that there is an interaction between gibberellin, whose production is initiated by wounding, and the inhibitor. Bacterial infection was not the cause of the results obtained.     

Renal vasculature and excretory system of the agamid lizard,Ctenophorus ornatus

The structure and ultrastructure of the vasculature and nephric tubules of the kidney of the Ornate Dragon Lizard, Ctenophorus (=Amphibolurus) ornatus, was investigated by light microscopy and scanning electron microscopy of resin casts. Compared with other agamid lizards, the arterial supply of only two arteries per kidney is small. The number of glomeruli per kidney in C. ornatus, at between 400 and 600, is low by reptilian standards and very low for lizards. The glomeruli are not only comparatively few in number but are also simple in the nature of their capillary configuration. These features are suggestive of a greatly reduced surface area for arterial filtration. In contrast to the small arterial supply, the afferent venous supply, the renal portal system (RPS), is substantial and forms an extensive capillary network throughout the kidneys. No venous shunts were found in the kidneys, suggesting that the venous network is functioning as a true portal system. Valves were not identified within the RPS, implying that neural control of general vascular tone could alter velocity and perhaps the direction of blood flow by changing pressure profiles. The nephroi are comparatively short and display features consistent with the production of urate precipitates as the primary nitrogenous waste product. A close association between the distal tubule (DT) and the glomerular hilus may demonstrate a simple form of a juxtaglomerular apparatus. The finding of aglomerular tubules indicates an important role for tubular secretion. The results of this study indicate that these lizards may have a reduced reliance on filtration for homoiostasis and a greater reliance on tubular secretion. © 1993 Wiley-Liss, Inc.     

Pharmacologic study of inflammatory processes. Modification of polynuclear neutrophil chemotaxis]

A study of rat polymorphonuclear chemotaxis has been made by a direct microscopic method and the effect of inflammatory reactions induced by carrageenan, calcium pyrophosphate and complete Freund's adjuvant has been studied. In addition the action of various drugs such as cholera toxin, colchicine, prostaglandins and certain immunomodulators, was investigated. The results have been analysed with special regard to the role of chemotaxis in inflammatory responses.