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Notes: In nine patients who gave birth to babies below the fifth centile in weight, serum urate concentration and fractional reabsorption of urate were significantly higher than in 25 control patients whose babies were of normal birth weight. Haemoglobin concentration and haematocrit were also significantly increased in the small-for-dates group. All of these changes may reflect depletion of extracellular fluid volume.

Notes: These experiments investigate events involved in triggering sugar accumulation in the cold in tubers of Solanum tuberosum L. cv. Desirée. Sugar content, 14C-glucose metabolism, metabolite levels and activities of sucrose phosphate synthase (SPS) and starch-degrading enzymes were followed after transfer to 4°C. (i) Net sucrose accumulation began between 2 and 4 d. By 10 d, reducing sugars were also increasing. From 20 d onwards, sugar accumulation slowed. Sucrose fell, but reducing sugars continued to increase. (ii) To measure unidirectional sucrose synthesis, U-[14C]glucose was injected into tubers after various times at 4°C. The tubers were then incubated for 6 h. After 1 d at 4°C, both the absolute and the relative (expressed as a percentage of the metabolized label) rates of sucrose synthesis decreased compared to those at 20°C. Between 2 and 4 d at 4°C, labelling of sucrose increased 3-fold, to over 60% of the metabolized label. This high rate was maintained for up to 50 d in cold storage. When tissue slices were incubated with 2.5 mol m−3 U-[14C]glucose, the rate of labelling of sucrose in slices from 6 d cold-stored material was higher than in slices from warm-stored material, irrespective of whether the incubation occurred at 4°C or at 20°C. (iii) Hexose-phosphates increased during the first day after transfer to 4°C. Their levels fell during the next 3 d, as sucrose synthesis increased. They then rose (until 20 d) and fell, in parallel with the rise and decline of sucrose levels. UDPglucose remained unaltered during the first 4 d, and then increased and decreased in parallel with sucrose. (iv) SPS activity assayed in optimal conditions and the total amount of SPS protein did not change. However, when assayed in the presence of phosphate and limiting substrate concentrations, activity rose 3–5-fold between 2 and 4 d. (v) Amylases and phosphorylases were investigated using zymograms to separate isoforms. Phosphorylases did not change. Between 2 and 4 d at 4°C, a new amylolytic activity appeared. (vi) Estimates of the specific activity of the phosphorylated intermediates and the absolute rate of sucrose synthesis (calculated from the 14C-labelling data and metabolite analysis) showed that changed kinetic properties of SPS and decreased levels of hexose-phosphate are accompanied by a 6–8-fold stimulation of sucrose synthesis. They also show that the final level of sugar is partly determined by a cycle of sugar synthesis and degradation. (vii) It is concluded that the onset of sugar accumulation in cold-stored tubers is initiated by a change in the kinetic properties of SPS and the appearance of a new amylolytic activity. It is discussed how other factors, including hexose-phosphate levels and subcellular compartmentalization, could also influence the final levels of sugars by altering the balance of sugar synthesis and remobilization.

Notes: Peroxidases are haem-containing enzymes capable of oxidizing a wide range of substrates. This article describes the presence of peroxidase activity in the growth medium of axenic Spirodela punctata (Lemnaceae) cultures. It was found that the release of extracellular peroxidase activity is specifically enhanced by phytotoxic, halogenated phenols but not by other abiotic stress-factors, elicitors or plant metabolites. Based on the concentration dependence of 2,4,6-trichlorophenol (TCP)-enhanced peroxidase release, it is concluded that release is not simply a consequence of physiological damage, but rather requires metabolically healthy fronds. In vitro studies (UV/VIS spectroscopy and liquid chromatography/mass spectrometry) show that the extracellular duckweed peroxidase (SpEx), which was partially purified from Spirodela growth medium, is capable of catalysing the oxidative dechlorination of TCP with hydrogen peroxide as the electron acceptor. It is proposed that the ability of S. punctata to specifically sense environmentally persistent phytotoxic chlorophenols, and to respond by increasing extracellular levels of a peroxidase capable of catalysing their oxidative dechlorination, is part of the protection strategy of this aquatic plant against xenobiotic stress.

Notes: Transfer of potato tubers to low temperature leads after 2–4 d to a stimulation of sucrose synthesis, a decline of hexose-phosphates and a change in the kinetic properties, and the appearance of a new form of sucrose phosphate synthase (SPS). Antisense and co-suppression transformants with a 70–80% reduction in SPS expression have been used to analyse the contribution of SPS to the control of cold sweetening. The rate of sucrose synthesis in cold-stored tubers was investigated by measuring the accumulation of sugars, by injecting labelled glucose of high specific activity into intact tubers, and by providing 50 mol m–3 labelled glucose to fresh tuber slices from cold-stored tubers. A 70–80% decrease of SPS expression resulted in a reproducible but non-proportional (10–40%) decrease of soluble sugars in cold-stored tubers, and a non-proportional (about 25%) inhibition of label incorporation into sucrose, increased labelling of respiratory intermediates and carbon dioxide, and increased labelling of glucans. The maximum activity of SPS is 50-fold higher than the net rate of sugar accumulation in wild-type tubers, and decreased expression of SPS in the transformants was partly compensated for increased levels of hexose-phosphates. It is concluded that SPS expression per se does not control sugar synthesis. Rather, a comparison of the in vitro properties of SPS with the estimated in vivo concentrations of effectors shows that SPS is strongly substrate limited in vivo. Alterations in the kinetic properties of SPS, such as occur in response to low temperature, will provide a more effective way to stimulate sucrose synthesis than changes of SPS expression.

Notes: Scanning electron microscopy (SEM) was employed to evaluate structural damage to blue crab (Callinectes saupidus) muscle resulting from thermal processing combined with freezing preservation in the course of developing the methodology for applying SEM to the study of processinglpreservation effects on muscle tissue. Specimens dissected from thermally processed, fast and slow frozen, conventionally frozen stored crabmeat were glutaraldehyde-fixed, solvent exchanged, freeze fractured, critical point dried, gold coated and examined and photographed with an Etec “Autoscan” microscope. Gross structural damage to the thermally processed tissue due to ice crystal formation and growth was clearly observable in low magnification (ca. 150×) micrographs of freeze-fractured transverse surfaces. Ice crystal formation and growth followed the well documented patterns associated with fast and slow frozen native (i.e., raw) muscle tissue studied in thin section by means of transmission microscopic techniques following conventional freezer storage. It was determined that the low magnification images best depicted gross structural damage to intact fibers or fiber bundles while high magnifications (ca. ≥1000×) depicted ultrastructural organization and damage quite satisfactorily. An accelerating voltage of 10 Kev was adequate for the former whereas 20 Kev proved superior in the latter case, although the risk of‘charging’ was increased at the higher voltage. An osmium post-fix was found to be unnecessary, gluteraldehyde being adequate. Freeze fracturing was essential for revealing‘intracellular’ damage especially, and critical point drying appeared to be superior to freeze drying prior to gold coating. Crustacean muscle is especially well suited to SEM study.

Notes: Many vertebrate predators consume a wide variety of prey types, depending upon availability and vulnerability. In contrast, striped bass, Morone saxatilis, that have been introduced to Lake Texoma (Oklahoma-Texas, U.S.A.) use a very limited array of fish (mostly clupeids of the genus Dorosoma) as prey. As a large, mobile predator, M. saxatilis should be capable of capturing and consuming numerous other species of fish that are available in the reservoir. However, examination of 1845 stomachs year-around over 5 years showed that the only marked ‘switching’ among prey was from Dorosoma to a diet including a high percentage of insects during spring–early summer, ignoring most other fish taxa that could have served as food. Even under essentially starvation conditions in late summer of years with scarce Dorosoma, M. saxatilis in Lake Texoma did not switch to other available fish as prey. Patterns of predation by M. saxatilis are trenchantly different from place to place: very narrow prey selectivity even under starvation conditions has been reported once previously for the species in a freshwater reservoir, but in its native marine and estuarine environment and in some other reservoirs the species is more catholic in its use of prey. Why this large predator shows fidelity in some environments to particular prey, even to the extent of starvation, remains an enigma.

Notes: When the judge of the High Court of Admiralty, Dr Julius Caesar, rode south from London to Lewes on 26 June 1591 1 an important experiment was initiated in the Admiralty court's continuing quest for greater respect and authority. The judge was setting out on a circuit of the troubled south and west coast of England in hopes of forcing the local authorities in those regions to submit to the supremacy of the High Court of Admiralty.2An examination of the prelude to the circuit and of the circuit itself, as well as an appraisal of its aftermath, will provide us with an instructive view of the tension between the local authorities and the central Government at the end of the sixteenth century. If there were a marked reduction in the quality of central government leadership at the end of Elizabeth's reign, one cause was perhaps the unsubdued strength of the provincescoupled with the corruption of Crown officers who were beyond the effective control of Westminster.

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