Characterisation of an mRNA encoding a human ribosomal protein homologous to the yeast L44 ribosomal protein.

We describe the isolation and characterisation of a full-length cDNA sequence (pZH-21) of a human ribosomal protein (rp) mRNA isolated from a cDNA library constructed from the human ZR-75-1 mammary tumour cell-line. The predicted protein is highly basic and shows 72% homology at the amino acid (aa) level with yeast rp L44. Comparative RNA blotting of ZR-75-1 poly(A)+ RNA isolated from cells cultured in the presence of the anti-oestrogen tamoxifen demonstrates the presence of a number of mRNA species whose concentration is elevated co-ordinately 5-6-fold in the presence of 17beta-oestradiol. Insulin in the presence of tamoxifen, also enhanced rp mRNA levels suggesting increased levels are a reflection of cell proliferation as opposed to specific hormonal regulation. Genomic analysis demonstrates the presence of a family of related human sequences, and homology with rat and guinea pig rp genes, but not yeast DNA. The conservation of rp aa sequence, in the absence of detectable homology at the nucleotide (nt) level, points to an important common functional role of the L44 protein in ribosome structure and function in man and yeast.

THE EFFECT OF MANGANESE ON ROOT EXTENSION OF GEUM RIVALE L., G. URBANUM L. AND THEIR HYBRIDS.

Root elongation of Geum rivale and G. urbanum grown in nutrient solution decreased as manganese concentration was increased above 25 mg dm-3 , especially in G. urbanum. Prior exposure of roots to 25 mg Mn dm-3 increased their capacity for subsequent elongation in manganese solutions, the effect of such pretreatment being most pronounced in G. rivale. G. rivale was significantly more tolerant of 50 mg Mn dm-3 than G. urbanum. Efflux of potassium from root segments, used as a measure of membrane permeability, was significantly higher in G. urbanum than in G. rivale at this concentration. Tolerance of 50 mg Mn dm-3 by progeny of hybrid individuals was generally related to morphological intermediacy, although there were some noticeable exceptions. Manganese tolerance of hybrids could not be consistently related to their known tolerance of waterlogging.

COMPARATIVE STUDIES OF PLANT GROWTH AND DISTRIBUTION IN RELATION TO WATERLOGGING: XIV. IRON, MANGANESE, CALCIUM AND PHOSPHORUS CONCENTRATIONS IN LEAVES AND ROOTS OF GEUM RIVALE L. AND G. URBANUM L. GROWN IN WATERLOGGED SOIL.

Geum rivale L. and G. urbanum L. were grown in drained, continuously flooded or transiently flooded compost for 21 weeks. Leaf and root material harvested after this time was analyzed for Fe, Mn, Ca and P. Mn and Fe concentrations in roots and leaves of both species were increased by flooding. Higher Fe concentrations accumulated in the roots, while Mn was present in roughly equal concentrations in both roots and leaves. Leaf Ca concentration of both species was higher than that of roots. Although Ca concentrations were significantly higher in G. rivale than in G. urbanum, there were no readily interpretable effects of waterlogging. P concentration was decreased in leaves and increased in roots of flooded G. urbanum, although there was much less effect of flooding on P concentration in G. rivale. Fe may be precipitated by phosphate in G. urbanum roots, but this may lead to P deficiency in shoots and roots, resulting in poor growth of this species in waterlogged soil. A different mechanism of Fe immobilization is likely to occur in G. rivale, which does not result in phosphorus deficiency.

EFFECTS OF ZINC ON CELL, NUCLEAR AND NUCLEOLAR SIZE, AND ON RNA AND PROTEIN CONTENT IN THE ROOT MERISTEM OF A ZINC-TOLERANT AND A NON-TOLERANT CULTIVAR OF FESTUCA RUBRA L.

The effects of a 4 d exposure to Zn on some cellular characteristics in the root meristem were investigated in seedlings of a Zn-tolerant cultivar of Festuca rubra L. (Merlin) and in a non-tolerant cultivar (S59). In S59, 0.1 and 0.2 µg Zn cm-3 resulted in a 7% and 17% reduction, respectively, in the mean area of mitotic cells compared with controls grown in the absence of Zn. Moreover, mean nuclear volume (13% and 28%) and total nucleolar volume (43% and 65 %) of G2 cells and RNA content (9 % and 44 %) and protein content (6 % and 17 %) of mitotic cells were also reduced by Zn. In Merlin, however, the mitotic cell area was 4 % and 19 % larger at 0.1 and 0.2 µg Zn cm-3 compared with the controls. Treatment with Zn also increased nuclear volume (13% and 47%) and total nucleolar volume (42 % and 86%), of G2 cells and RNA content (40 % and 32 %) and protein content (8 % and 33 %) of mitotic cells. The concentration of protein in mitotic cells was also increased by Zn treatment in Merlin. The data are discussed in relation to the previously established effects of Zn on the duration of the cell cycle in these cultivars.

PHENOTYPIC FLEXIBILITY OF CAREX FLACCA SCHREB.: TOLERANCE OF SOIL FLOODING BY Populations FROM CONTRASTING HABITATS.

Nine populations of Carex flacca Schreb., collected from sites which vary widely in their liability to soil flooding, were grown on an experimental soil with free drainage, transient flooding or continuous flooding for 26 weeks. Although the flooding treatments resulted in low redox potentials and high concentrations of reduced iron and manganese in the soil, the growth of C. flacca plants was little affected by flooding. All populations grew equally well on the flooded soils. All populations produced adventitious roots at the soil surface in the flooded treatments; these were absent from plants grown on the freely drained soil. Flooding produced an increase in the manganese concentration of roots and shoots but, although the iron content of roots was markedly increased by flooding, there was no increased transport to the shoots. In view of the absence of detectable phenotypic differentiation between these populations from widely contrasting sites and their unimpaired growth on severely waterlogged soils, it is argued that C. flacca plants have a broad tolerance (phenotypic flexibility) of soil flooding. This may be important in the wide ecological amplitude of this species.

Variation in DNA C value in natural populations of Dactylis glomerata L.

DNA C values were determined for eighteen natural populations of Dactylis glomerata L. collected from various sites in Europe to examine the extent of intraspecific variation in C value and how this variation may be related to latitude and altitude of origin. A sub-set (8) of these populations represent an altitudinal transect (350-1120 m) in northern Spain whilst the remainder represent a latitudinal range (38.53-57.47 °N). Preliminary experiments established optimum acid hydrolysis times for the Feulgen reaction of 62 min and 20 min for D. glomerata cv. S26 and the standard Hordeum vulgare L. cv. Sultan (C = 5.6 pg), respectively. The data emphasize the necessity of using the optimum hydrolysis time for both the standard and unknowns for C value determination, whether using 5 M HCl at 25 °C or 1 M HCl at 60 °C. This procedure has not been followed in the majority of published estimates of C value. Seventeen of the natural populations were tetraploid (2n= 4x= 28) whilst the southernmost population was diploid (2n= 2x= 14). The 17 tetraploid populations exhibited a 28.7 % variation in DNA C value, ranging from 4.35 to 5.60 pg, whilst the C value of the diploid population was 3.3 pg. There was neither a significant relationship between the C value and latitude of origin of the 10 populations which comprised the latitudinal transect (1 diploid and 9 tetraploid) nor with the tetraploids alone. However, the C values of the eight populations which formed the altitudinal transect in the Galicia mountains in N. Spain were negatively correlated with their altitude of origin. Possible reasons for this relationship are discussed.

Polyamine spider toxins are potent un-competitive antagonists of rat cortex excitatory amino acid receptors.

We examined the effect of argiopine and argiopinine 3, low molecular weight polyamine venom components of the spider Argiope lobata, on rat cortical excitatory amino acid (EAA) receptors expressed in Xenopus oocytes. Responses to 100 microM N-methyl-D-aspartate (NMDA) with 10 microM glycine were blocked by both of the polyamine toxins in a dose-dependent manner. Both compounds had similar potencies against 100 microM kainate or 50 microM (S)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (L-AMPA). Oscillatory responses to 2 microM quisqualate were unaffected by either polyamine toxin. Increasing concentrations of either NMDA, kainate or AMPA were unable to overcome the antagonism by either spider toxin. We were able to demonstrate a use-dependent phenomenon similar to that of phencyclidine; neither polyamine toxin affected the NMDA, kainate or AMPA response without the presence of the respective agonist.

Barium ions fail to support neurotransmission at a central synapse.

Synaptic transmission in the CA1 area of the hippocampal slice preparation in vitro was studied in bathing media containing different levels of divalent cations. Transmission was abolished by replacing the normal levels (2.5 mM) of Ca2+ with 3 mM Mg. Transmission was not permanently restored by subsequent addition of Ba2+ but added Ca2+ was effective. Transient reappearance of synaptic currents were seen when Ba2+ was added at a time when contaminating levels of Ca2+ were still present, but neurotransmission waned as [Ca2+]e declined with protracted washout. In accordance with this interpretation, Ba2+ potentiated the transmission observed in the presence of low concentrations (0.25 mM) of Ca2+. Little evidence was found for Ba2+ effects at axonal sites but the potentiation of synaptic transmission by Ba2+ could be accounted for in terms of a blockade of terminal K-channels.

Vibration as a possible explanation for putative electromagnetic field effects: a case study on marine diatoms.

PURPOSE: We examined the conjecture that mechanical vibration, being an uncontrolled and variable factor from one trial to another, might explain the inconsistency of results from investigations of the influence of extremely low frequency electromagnetic fields on the Ca-dependent motility of marine diatoms (Amphora coffeaeformis, strain #2038). MATERIALS AND METHODS: Owing to slight differences in culture of diatoms in previous studies, culture techniques are described in detail here. Diatoms showed maximal motility in logarithmic growth and motility was dependent on external [Ca], reducing at <.25 mM added Ca. Ninety-six different vertical vibration treatments were applied to the petri dishes containing the agar on which the diatoms were placed. The envelope of amplitudes varied from 50-500 pmicro at 10Hz to 100 nm-l1mmicro at 500 Hz. RESULTS: No significant effect of the mechanical vibrations on the motility response of diatoms was observed. We were unable to impose deliberate vibrations in a horizontal direction though some component of horizontal movement was probably present in our tests. CONCLUSIONS: The results imply that the variability of earlier experiments with extremely low frequency electromagnetic fields is unlikely to be ascribable to mechanical vibration.

Diatom motility: the search for independent replication of biological effects of extremely low-frequency electromagnetic fields.

PURPOSE: To investigate the hypothesis that exposure to a certain combination of static and time-varying electromagnetic fields (EMF) results in an increase in motility of the marine diatom Amphora coffeaeformis. MATERIALS AND METHODS: Diatom motility on agar was positively correlated with calcium ion (Ca2+) concentration. In previous experiments extremely low frequency EMF (16 Hz) had the greatest effect on diatoms at suboptimal for movement Ca2+ concentrations. To ensure that the required suboptimal Ca2+ concentration and resultant cell motility were found, a number of low concentrations of Ca2+ were experimentally tested. The EMF exposure conditions were those at the calculated calcium resonances (B(V)=0 microT; B(H)=20.9 microT; B(AC)=41.8 microT peak-peak 16 Hz) previously found to cause enhanced motility. Diatom movement on agar plates under EMF and control exposures was recorded. RESULTS: There was no significant difference in cell motility between control and EMF-exposed diatoms at each Ca2+ concentration tested. CONCLUSIONS: The study indicates that low-frequency EMF set at resonance conditions did not cause an increase in motility of the diatoms.

Rates of platination of -AG- and -GA- containing double-stranded oligonucleotides: effect of chloride concentration.

The kinetics of the reactions between 15N-labelled cisplatin and 14-base pair duplex oligonucleotides with either 5'-AG-3' or 5'-GA-3' groupings as the principal platination site are examined in the presence of 60-80 mM chloride by [1H,15N]HSQC 2D NMR spectroscopy. The presence of chloride at these concentrations results in a five-fold decrease in the rate of hydrolysis of cisplatin to cis-[PtCl(NH3)2(OH2)]+ and a two- to twenty-fold decrease in the rate of monofunctional adduct formation. The effects on the rate of closure from monofunctional to bifunctional adducts are less well established but some of these rates appear not to be significantly reduced by the presence of added chloride. The results provide a caution that the use of chloride to quench platination reactions may not be fully effective.

Arthroscopy of the first metatarsophalangeal joint.

We carried out 12 arthroscopies of the first metatarsophalangeal (MTP) joint in 11 patients over a five-year period. Their mean age was 30 years (15 to 58) and the mean duration of symptoms before surgery was eight months (1 to 24). Six patients had an injury to the joint; all had swelling and tenderness with a reduced range of movement. In six patients, radiographs revealed no abnormality. Under general anaesthesia with a tourniquet the hallux is suspended by a large Chinese finger trap to distract the joint. Using a 1.9 mm 30 degree oblique arthroscope the MTP joint is inspected through dorsomedial and dorsolateral portals with a medial portal if necessary. All patients were found to have intra-articular pathology, which was treated using small instruments. The mean follow-up was 19.3 months (6 to 62) and all patients had no or minimal pain, decreased swelling and an increased range of movement of the affected joint.

The orthopaedic management of peripheral ischaemia in meningococcal septicaemia in children.

Between March 1993 and February 1999, 14 children aged from eight months to 14.75 years were admitted to the paediatric intensive-care unit with meningococcal septicaemia in association with severe peripheral ischaemia. Of these, 13 were operated upon, eight of whom had early fasciotomies. Five children died. Of the nine survivors, one had no amputations while in the other eight 14 limb segments were amputated. We review the case histories and propose a protocol for the early management of these children.

Measurement of biologically available organic material in intertidal sediments subject to inputs of sea coal or colliery wastes.

A method for the measurement of biologically available organic matter in intertidal or subtidal marine sediments subject to an input of sea coal or colliery wastes is described. The method involves boiling sediment in hydrogen peroxide (H2O2) for 4 h at 160 degrees C to dissolve non-colliery waste organic matter which is then recorded as weight lost after rinsing and drying. Samples are then ashed at 495 degrees C to determine the weight of coal or colliery wastes present. Although H2O2 shows a slight reaction with colliery wastes (overall mean of 0.86% weight loss), it is appropriate to use this technique for the determination of organic matter available to sediment-dwelling biota. We show that shore organic content should not be determined merely by ashing sediment, even on shores which do not appear to contain wastes, since even visibly 'clean' shores in north-east England generally contain some coal fragments in their sediment. Our method is suitable anywhere where biologically available organic matter needs to be measured independently of waste content, e.g. in terrestrial systems close to centres of mining activity.

Evidence for abrasion and enhanced growth of Ulva lactuca L. in the presence of colliery waste particles.

Previous studies have highlighted a reduction in occurrence and biomass of Ulva lactuca L. (Chlorophyceae) on shores where inputs of colliery waste occur. It was postulated that this was owing to an abrasive effect of colliery waste on macroalgal fronds. To test this, individual U. lactuca plants were exposed to colliery waste (three different grain size categories: < 500 microm, 500-2000 microm, and 0-2000 microm) in both shaken (turbulent) and still conditions in the laboratory. Over an 8-day period, U. lactuca plants lost weight when colliery waste was present and gained weight when no colliery waste was present. Weight loss was most pronounced in U. lactuca exposed to colliery waste of 500-2000 microm grain sizes in shaken conditions (- 18.8% +/- 4.65 SE, n = 4). However, greatest weight gain (+ 26.8% +/- 6.26 SE, n = 4) also occurred in the presence of colliery waste (0-2000 microm), but in still conditions. Weight gain was also observed after 60 days in still conditions in the presence of colliery waste (grain sizes 0-2000 microm); U. lactuca showed significant growth (+ 69% +/- 67 SE of starting weight, n = 5) compared with controls (- 51% +/- 41 SE, n = 5). These results suggest that 'large' grains of colliery waste act as a physical abrading agent on macroalgae when in turbulent conditions, and may be responsible for lowering of species richness of macroalgae where colliery waste inputs occur. However, by contrast, colliery waste in still conditions promotes the growth of U. lactuca, suggesting that, for example, rock pool flora may benefit from its presence

The effects of zinc on cell viability and on mitochondrial structure in contrasting cultivars of Festuca rubra L. - a rapid test for zinc tolerance.

A 20-min exposure to 5.0 microg Zn cm(-3) reduced the percentage of viable root meristematic cells in three cultivars of Festuca rubra L.: Merlin (Zn-tolerant), Hawk (salt-tolerant but with a degree of Zn tolerance) and S59 (Zn-sensitive). The Zn-induced cell mortality in S59 was approximately twice that of the tolerant cultivars. The mean area of mitochondrial profiles in root meristematic cells of Zn-untreated roots was similar in S59 and Merlin but that of Hawk was smaller. A 4-day exposure to 0.2 microg Zn cm(-3) resulted in mitochondrial swelling in the Zn-sensitive cultivar; there was a 25% increase in the mean area of mitochondrial profiles in this cultivar, but no significant increase occurred in Hawk or Merlin. Zn treatment caused a collapse of the cristae and a localized condensation of the mitochondrial matrix in S59, but not in Hawk or Merlin. The marked increase in cell mortality after only a 20-min Zn exposure and the relative simplicity of the technique, indicates that this procedure could be used as a rapid and independent measure of Zn tolerance.

Effects of colliery waste on littoral communities in north-east England.

Colliery waste input has a detrimental effect on the species richness and alpha diversity of sandy and rocky shore communities in north-east England. On sandy shores at the shore levels Chart Datum (CD) + 1.2 to 1.5 m (low shore) and CD + 2.7 to 3.0 m (mid-shore), a maximum of two species of macroinvertebrates per shore level was found at sites heavily contaminated by colliery waste input. In contrast, typically about eight species were found at uncontaminated shores. At the shore level CD + 4.2 to 4.5 m (high shore), the species richness and diversity of fauna were not detectably affected by colliery waste input. On rocky shores that were uncontaminated, 12-15 species of macroalgae were found, whereas only five to eight species were found at contaminated shores. The absentees were usually ephemeral, early successional species. Macroalgal biomass, although less at contaminated shores, showed no significant relationship with colliery waste input. However, the alpha diversity of animal communities on rocky shores was, on occasions, significantly increased where colliery waste inputs occurred. The physical properties of colliery waste are likely to be the reason for the effects observed on both sandy and rocky shores, since many of the leachable chemicals in colliery waste are leached during the period that it spends on the sea bed before accumulating in the intertidal zone.

Effects of trematode parasitism on the behaviour and ecology of a common marine snail (Littorina littorea (L.)).

Cryptocotyle lingua (Creplin) is a digenean trematode parasite of the littoral prosobranch gastropod Littorina littorea (L.). The literature suggests the snails become infected by grazing guano of the final host, the herring gull, Larus argentatus Pontoppidan. The parasite emerges from the snail as free-swimming cercariae. Interactions between the snail and the parasite at cellular and life-history levels are well established, but little is known of the influences the interaction has on the behaviour and the ecology of the snail. We tested the response of the snail to encounters with cercariae, examined the longevity of the guano on-shore and tested the responses of the snail to encounters with guano. Over half the L. littorea tested were able to detect both cercariae and a filtered homogenate of cercariae in conspecific mucus trails, approximately one-third of animals refusing to cross the treatments. Chemoreception by the mouth or foot is considered the most likely means of detection. Guano samples (mean weight 3.22 g) naturally deposited at approximately mid-tide level were completely washed away by one tidal inundation. We consider this period too brief to allow for ingestion of eggs in guano by the snail. Further, snails would not cross guano placed in conspecific trails. Most snails would not cross guano diluted by 10(3)x(10 mg ml(-1)) and some snails could still detect guano diluted by 10(6)x(10 &mgr;g ml(-1)), though all were prepared to cross it. Detection of guano is again believed to be by chemoreception by the mouth or foot. These results are discussed in terms of the mating and aggregating behaviour of L. littorea. Ingestion of the parasite by L. littorea is likely to take place once the guano has washed away as the eggs are negatively buoyant in seawater and may adhere to rock (biofilm) or algal fronds which may be grazed by the snail.

Intercuneiform instability and the "gap" sign.

We describe three cases of low-energy injuries to the midfoot resulting in rupture of Lisfranc's ligament without tarsometatarsal injury. Examination of the feet revealed an obvious physical sign only on weightbearing, and all three patients were noted at surgery to have intercuneiform instability in association with a rupture of Lisfranc's ligament.

Metatarsal neck osteotomy with rigid internal fixation for the treatment of lesser toe metatarsophalangeal joint pathology.

Metatarsalgia associated with metatarsophalangeal (MTP) joint instability and/or plantar callosity formation is a difficult problem to treat. During a 15-month period, we performed 50 osteotomies of the metatarsal neck with rigid internal fixation in 47 feet of 42 patients. Three patients were excluded from the study, leaving 47 osteotomies in 44 feet of 39 patients for review. There were 6 men and 33 women, with a mean age of 57 years. In addition to lesser MTP joint pain with or without instability, the majority of patients had first ray pathologic condition, which was also addressed at the time of surgery. All but one of the osteotomies were united radiologically at 6 weeks. The mean shortening was 4.1 mm (range, 2-12 mm), and the mean follow-up was 9 months. There were no cases of malunion, nonunion, or avascular necrosis. At follow-up, 33 patients were asymptomatic. Eight patients (nine feet) had a degree of persisting pain at follow-up (seven mild and two moderate), but the source of this pain was only the metatarsal or MTP joint that was operated on in three cases. In this article, we describe the indications, the technique, and the results of the osteotomy.