bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of chilling on the diurnal rhythm of enzymes involved in protection against oxidative stress in a chilling‐tolerant and a chilling‐sensitive maize genotype
Authors: Kocsy Gábor , Owttrim George , Brander Karl , Brunold Christian 
Published: May 2006

The effect of chilling on diurnal changes in activity of adenosine 5′‐phosphosulfate sulfotransferase, glutathione reductase (EC 1.6.4.2) and glutathione transferase (EC 2.5.1.18) was analysed in the second leaf of Z 7, a chilling‐tolerant, and Penjalinan, a chilling‐sensitive maize (Zea mays L.) genotype. Nitrate reductase (EC 1.6.6.1) was measured for comparison. All enzyme activities examined changed with a typical diurnal rhythm in both genotypes cultivated at 25°C. Adenosine 5′‐phosphosulfate sulfotransferase and nitrate reductase activity peaked during the light period, then decreased and reached lowest levels at the end of the dark period. Glutathione reductase activity increased in the dark and decreased during the light period. Maximum glutathione transferase activities were measured in the middle of the light period, minimal ones in the middle of the dark period. At 12°C these diurnal changes were eliminated in all enzymes examined of both genotypes.The average adenosine 5′‐phosphosulfate sulfotransferase and glutathione reductase activity were higher in the chilling‐tolerant Z 7 than in the sensitive Penjanilan at 12°C in the light. Increased levels of both enzymes may contribute in establishing increased levels of cysteine and reduced glutathione in the chilling‐tolerant Z 7. Indeed it has been shown before that the chilling‐tolerant maize genotypes contain higher levels of both compounds at low temperatures than chilling‐sensitive ones.
Differential expression of Bcl‐2, Bcl‐XL and p53 in colorectal cancer
Authors: Han Hye Seung , Park Young‐Mee , Hwang Tae Sook 
Published: May 2006

AbstractAims:  The balance between proliferation and apoptosis is often disturbed in cancer. The aim of this study was to investigate the possible role of Bcl‐2 gene family members and p53 as prognostic factors in a series of colorectal cancer.Methods:  The immunohistochemical expression of Bcl‐2 gene family members (Bcl‐2 and Bcl‐XL) and p53 was evaluated in 81 surgical specimens of primary human colorectal cancers to establish the role of these genes in colorectal cancer and to evaluate their prognostic importance.Results:  The expression of Bcl‐2 correlated with early clinical stage and lack of lymphovascular invasion and lymph node involvement. The expression of p53 correlated with less differentiated status and with perineural invasion. p53 expression showed negative correlation with Bcl‐XL expression (P = 0.025) and no correlation with Bcl‐2 expressionConclusions:  p53 expression may be a less favorable marker and Bcl‐2 expression a more favorable marker of behavior. Bcl‐2 and Bcl‐XL may play an independent role in disease progression, and the expression of these proteins may be under independent regulatory control in colorectal cancer.
New growth factor therapies aimed at improving intestinal adaptation in short bowel syndrome
Authors: Pereira Prue M , Bines Julie E 
Published: May 2006

AbstractShort bowel syndrome (SBS) is used to describe a condition of malabsorption and malnutrition resulting from the loss of absorptive area following massive small bowel resection. The key to improved clinical outcome after massive small bowel resection is the ability of the residual bowel to adapt. Although still in experimental stages, a major goal in the management of SBS may be the augmented use of growth factors to promote increased adaptation. A number of growth factors have been implicated in promoting the adaptation process. The best‐described growth factors are reviewed: glucagon‐like peptide‐2 (GLP‐2), epidermal growth factor (EGF), and growth hormone (GH). This article reviews the ability of recombinant GLP‐2, EGF and GH to modulate structural and functional aspects of intestinal adaptation following small bowel resection. Although these growth factors have shown promise, small sample size, inconsistent measurement parameters and uncontrolled study designs have hampered the acquisition of strong data advocating the use of growth factor treatment for SBS. Multicenter trials using well‐defined outcome measures to assess clinical efficacy are needed to direct the clinical indications, timing and duration of therapy and assess potential risks associated with growth factor therapies.
STUDIES IN THE BEHAVIOUR OF THE RHIZOME OF AGROPTRON REPENS(L.) BEAUV.
Authors: PALMER J. H. 
Published: May 2006

(1) The mode of growth of the rhizomatous grass Agropyron repens (Couch Grass) is described. The plant produces new rhizomes in the spring from basal lateral buds. The tip of each rhizome grows in a horizontal direction below the soil surface during the spring and summer before erecting in the autumn to form a primary aerial shoot. This shoot develops into a mature plant during the following year.By sampling a mature stand of Agropyron plants it is shown that the development of the primary shoot is marked by the production of a succession of leaves, internodes and lateral shoots which vary in length or form according to a well‐defined pattern. Usually 7 lateral buds at the base of the primary shoot grow out in the spring to form lateral shoots. Of these, the four most basal ones develop into rhizomes and the remainder into tillers. Plants growing in open communities develop differently in that secondary tillers and rhizomes are formed during the first growing season. Rhizome growth is not related to flower formation.(2) From experiments it is found that:(a) Rhizome growth can be induced during the winter under warm greenhouse conditions by increasing the intensity of illumination of the plants to within the range 500–2000 ft. candles.(b) No rhizome growth occurs under natural conditions when the illumination intensity is reduced to approximately 3 per cent of the noon summer value.(c) When rhizome growth is induced to begin approximately 4 weeks prematurely, then rhizome growth ceases in Mid‐July.(3) These results are discussed. It is concluded that rhizome growth is dependent upon the plant being brightly illuminated and that rhizome initiation in the spring is controlled by environmental factors, while rhizome cessation among plants in closed communities is most probably the result of the parent aerial shoots becoming senescent.The problem of the orientation of the rhizome and its depth adjustment in the soil will be considered in a later paper.The work described here was carried out in the University of Sheffield, England. The author is indebted to Professor A. R. Clapham for much invaluable advice and criticism. Grateful acknowledgment is made to the Department of Scientific and Industrial Research for a maintenance allowance which made this investigation possible.
THE SODIUM, POTASSIUM AND PHOSPHORUS CONTENTS OF TREE SPECIES GROWN IN CLOSE STANDS
Authors: OVINGTON J. D. , MADGWICK H. A. I. 
Published: May 2006

SummaryThe percentages of sodium, potassium and phosphorus on a dry weight and ash basis at different positions in the boles and canopies of a number of trees from three experimental areas are given.The total weights of sodium, potassium and phosphorus in the individual trees and in the tree crop are estimated.Comparisons are made of the sodium, potassium and phosphorus contents of the various components of the ecosystems in different woodland types.The balance of nutrients in woodlands is discussed in relation to the need for soil conservation.We should like to express our gratitude to the Forestry Commission who allowed us to sample the trees in the experimental plots. Unfortunately, it is not possible to include all the primary data that have been collected but they can be obtained on application to the Nature Conservancy or to the authors.
THE BASIDIOMYCETES OF SKOKHOLM ISLAND XIV. STABILITY OF THE MYGOTA
Authors: PARKER‐RHODES A. F. 
Published: May 2006

SummaryA method of estimating the stability of fungal populations from suitable field records is described, applicable to the Basidiomycetes. When significant instability is found the method also allows one to estimate the rate of change involved, and over a sufficient period also changes in the rate of change, at least qualitatively. These methods have been applied to data on the Basidiomycetes of Skokholm Island, collected from 1947 to 1956 inclusive.It was found that the lignicolous species were increasing, but that there was no overall change for practicolous, pteridietal, or coprophilous species. Within the praticolous group, however, two families, Agaricacei and Lycoperdacei, were in decline, while three, Clavariacei, Tricholomatacei and Cortinariacei, were increasing. There was evidence also of a change in composition of the mycota in the lignicolous group and among praticolous Cortinariacei (which were mainly Stropharioidei). The fungi of the Armerietum, a small group, appeared to be rapidly increasing. Temporary fluctuations in numbers, not much less in magnitude than these overall changes, ha'd occurred also in the pteridietal species and in the praticolous Hygrophoracei and Rhodophyllacei. No adequate evidence was found that any of these changes were accelerating or decelerating during the period.The magnitudes of the rates of change observed, on a per species basis, were mostly less than 1 per cent per annum; but the Clavariacei had increased and the Lycoperdacei decreased at considerably greater rates, but these were both small groups. The general conclusion was that the Skokholm mycota is in a rather stable condition.
ON THE MECHANISM OF SUGAR UPTAKE BY FLOATING LEAF DISKS
Authors: PENNELL G. A. , WEATHERLEY P. E. 
Published: May 2006

SummarySugar uptake by leaf disks of Atropa belladonna floating on sugar solution was measured as increase in dry weight of the disks.Evidence of the importance of metabolism in sugar uptake was established as follows:(a) Uptake was reduced by as much as 75 per cent under anaerobic conditions. Uptake equal to that in air took place with a partial pressure of oxygen as low as 2 per cent. At this oxygen concentration 65 per cent of the full rate of aerobic respiration occurred.(b) Uptake was considerably reduced by cyanide, azide and 2–4‐di‐nitro‐phenol.(c) The relationship between rate of uptake and external concentration was not linear, the increment in rate getting progressively less with increasing concentration.(d) Competition occurred between sugars of similar structure.(e) Chemical structure of the absorbed sugar played an important part in defining penetrability.The uptake persisting under anaerobic conditions was designated ‘passive’, and this subtracted from the uptake in air gave the ‘active’ component of the uptake in air.Chromatographic carbohydrate analyses of the disks revealed that ‘passive’ uptake resulted solely in an increase in sucrose content which reached a constant level within 2 hours. This is interpreted as equilibration of the apparent free space with the external solution.Under aerobic conditions a higher level of sucrose content was achieved. This is thought to be due to transfer of sucrose into an ‘inner‐space’, possibly the vacuole. In addition synthesis of polysaccharide occurred and it was this continued synthesis which led to persistent sucrose uptake from the medium.When disks which had been floating on sugar solution were transferred to water, they lost sugar. The quality and quantity of this leakage is consistent's with the hypothesis outlined above.It is concluded that the processes involved in sugar uptake were (a) diffusion into the outer space, (b) facilitated diffusion into an inner space, (c) synthesis of polysaccharide. There was no evidence of any ‘uphill’ transport being involved.
AESTIVATION IN RANUNCULUS REPENS L.
Authors: CUNNELL G. J. 
Published: May 2006

SummaryThe aestivation of the calyx and corolla in 640 mature flower buds of Ranunculus repens from two sites near London is recorded.Only two forms of quincuncial arrangement of the calyx are found and in almost equal numbers. One form is the mirror‐image of the other and they continue the spiral from the prophylls in the left or right direction respectively.All thirty‐two possible arrangements of the corolla are found in both samples but their frequencies are very unequally distributed. There are more quincuncial and less apotactous and convolute forms than is expected by chance alone.At the three posterior positions the two possible overlaps are more or less equally frequent overall, but there is a high correlation between the type of calyx and direction of the overlap. The predominating overlap is the eutopic one, i.e. the overlap at each position found in the corolla arrangement which continues the 2/5 spiral from the calyx. Overlaps involving the anterior petal appear to be entirely due to chance although in the site 1 sample there is a significant tendency to metatopy where the anterior and right lateral petals overlap.These observations are compared with published work on aestivation in other species with variably imbricate pentamerous corollas and their significance is briefly discussed.
POST‐GLACIAL DEPOSITS IN SOUTH YORKSHIRE AND NORTH LINCOLNSHIRE
Authors: SMITH A. G. 
Published: May 2006

SummaryThe stratigraphy and pollen analysis of Hatfield Moors, Yorkshire, about ten miles south of Goole, are described. These moors are the residue of an old raised bog which lies on the Triassic sandstones and has no underlying deposits indicative of an initial phase of reed‐swamp. The bog, which has at least four flooding horizons, began to grow in early Atlantic times. Early agricultural practices are revealed by the pollen analyses at the opening of Sub‐boreal times, and at the same time small amounts of charcoal are found in the peat. Agricultural activity increased at the beginning of Sub‐atlantic times, but was afterwards curtailed. It is suggested by comparison with a site at South Ferriby in the Ancholme Valley, Lincolnshire, that this curtailment may well date from the end of Romano‐British times.The stratigraphy and archaeology at Island Carr, Brigg, in the Ancholme Valley are brought together, and a correlation is made between the Bronze Age‐Iron Age transition; the opening of Sub‐atlantic times; and the onset of a marine transgression of the Ancholme Valley. This transgression occurs during a period of relative emergence in the East Anglian Fenland and it is possible that differential isostatic or tectonic movements have taken place between the two areas during the later part of the post‐glacial period. The possibility of the presence of offshore bars, however, complicates the problem. The transgression is also manifested at Redbourne Hayes, a site some five miles to the south of Brigg where the maximum of the transgression is shown, at a rather later date. The peat overlying the transgression clay at Redbourne Hayes probably dates from Romano‐British times and is—perhaps within rather wide limits—contemporaneous with the upper organic deposits at South Ferriby (where Romano‐British remains were found in situ) at Weston Road, Goole, and at Ingoldmells on the Lincolnshire coast.A reassessment is made of the dating of the site at Ingoldmells in which it appears that the deposits are more comparable with those of the Humber region than with those of the Fenland.
THE RELATION OF LEAF WATER DEFICIT TO SOIL MOISTURE TENSION IN PINUS SYLVESTRIS L.
Authors: RUTTER A. J. , SANDS K. 
Published: May 2006

SummaryDiurnal variation in the water balance of 2–3 year Pinus sylvestris in pots has been compared at four levels of soil moisture during 24 hours.The physical component of the soil moisture suction was measured with tensiometers and gravimetric gypsum blocks and estimated as o.1, 0.5, 1–2 and >5 atmospheres for the four levels. Leaf water deficit was expressed as a percentage of the water at turgidity, transpiration as the loss in fresh weight of a leaf sample during 1–11 minutes after cutting, and stomatal opening was measured by infiltration with alcoholic gentian violet.Increase in soil moisture tension caused a progressive increase in leaf water deficit, and a decrease in transpiration and stomatal opening, the latter being reduced both in number of open stomata and in the time for which they remained open during the day.The relative value of these measurements as indices of plant water balance and of soil moisture conditions is discussed together with a brief consideration of the relation between transpiration rate and soil moisture.It is concluded that leaf water deficit, transpiration and stomatal opening all reflect increase in soil moisture suction but that, during the day, they are affected also by other factors which obscure the direct effect of soil moisture. However, in the case of leaf water deficit an equilibrium is attained between plant and soil before sunrise. If measured in the morning, before the onset of stomatal transpiration, leaf water deficit appears to be closely related to the soil moisture conditions experienced by the plant. This measurement is suggested as the best plant index of the soil moisture suction in the vicinity of the roots.The persistence of appreciable deficits in wet, drained soil indicates that factors other than the physical soil moisture tension oppose water uptake.
NATURAL HYBRIDIZATION OF AGROSTIS TENUIS SIBTH. AND A. STOLONIFERA L.
Authors: BRADSHAW A. D. 
Published: May 2006

SummaryThere seems to be little barrier to natural hybridization between Agrostis tennis Sibth. and A. stolonifera L. The F1 hybrid is vigorous: but it is relatively sterile.The analysis of natural mixed populations of these two species from an old grazing meadow by means of a morphological index and by pollen fertilities shows that over a large central area of the meadow, plants indistinguishable from Fl hybrids are very abundant, to the virtual exclusion of the parental species which would be expected in such a habitat. A more elaborate morphological and cytological analysis confirms this, but suggests that there is also a small percentage of plants belonging to F2 and backcross generations.The success of the hybrid is due to its growth habit, which is better adapted to grazing conditions than that of either parent. Under grazing conditions reproductive sterility is no disadvantage.The hybrid populations are made up of a large number of different individual F1 hybrid plants, and cannot be due to the spread of one hybrid plant throughout the meadow, but to the repeated formation of the hybrid. Preliminary examination of other habitats suggests that the hybrid is more common than previously suspected.Discussion from an ecological standpoint suggests that the success of natural sterile hybrids depends on the possession of strong powers of vegetative propagation originally derived from the parental species. For this reason Agrostis tennis stolonifera is particularly successful. There are, however, other contributory factors.Discussion from a genetical standpoint suggests that since the hybrid is sterile and subsequent generations are uncommon, the two species are likely to remain quite distinct, but that gene flow between them cannot be ruled out without further investigation.
THE NUCLEOLI AND RELATED STRUCTURES IN THE DESMIDS*
Authors: KING G. C. 
Published: May 2006

SummaryThe nucleoli of nineteen species from thirteen genera of desmids have been investigated, and in these, four main types of nucleolar structure have been found. The activity of the nucleoli during mitosis and the presence of nucleolar‐organizing chromosomes is described. The presence of a substance resembling Geitler's ‘nucleolar substance’ in Spirogyra is recorded.
THE BALLISTICS OF SORDARIA
Authors: INGOLD C. T. , HADLAND SUSAN A. 
Published: May 2006

SummaryThe structure of the perithecium of S. fimicola is redescribed. The horizontal distance of spore discharge is studied. Spores may be shot to a distance of up to 10.5 cm. The spore deposit from horizontal discharging perithecia contains spore groups (projectiles) of all possible sizes (i.e. with 1, 2, 3, 4, 5, 6, 7 or 8 spores). The more spores in a group the greater the mean distance of discharge. The existence of the different sizes of projectile in the deposit suggests that the spores tend to stick together, but separation may occur during discharge at any of the seven intervals in the row of eight escaping spores. On the assumption that a break is equally likely at any of these intervals, it is shown that the numbers of projectiles of the different sizes agree closely with expectation. The tendency of spores to stick together is greater at low than at high temperature. The mean distance of horizontal discharge of 8‐spore projectiles is about 20% higher at 21–24°C than at 7–10°C.Ascus jets discharging vertically have been analyzed by catching them on a rapidly rotating (c. 24 rev. per sec) horizontal disk of transparent ‘Perspex’. The results confirm the view that a break in the row of eight escaping spores can occur at any of the seven possible points of breakage.The initial velocity of the ascus jet is computed by two independent methods, both giving values of the same general order of magnitude.
STUDIES ON THE GROWTH OF EXCISED ROOTS
Authors: CHARLES H. P. , STREET H. E. 
Published: May 2006

SummaryYeast extract was found to enhance the growth of the excised roots of a Czechoslovakian strain of groundsel. Effects of yeast extract were reproduced by a mixture of L(‐)‐tryptophane and DL‐methionine. β‐indolylacetic acid (IAA) had similar growth‐promoting effects to tryptophane.When roots were grown in medium containing either tryptophane or IAA for one passage and then subcultured into arginine medium they showed a marked stimulation of growth, particularly of their lateral roots. This growth stimulation, referred to as the ‘indirect’ effect of tryptophane and IAA, was greater than that observed when the roots were subculture into the same tryptophane or IAA medium for their second passage rather than into arginine medium.1‐naphthoxyacetic acid (1‐NOA) was not directly stimulatory in Passage 1 but caused an ‘indirect’ stimulation of growth in a subsequent passage in arginine medium. 2‐naphthoxyacetic acid (2‐NOA) caused a much greater ‘direct’ enhancement of growth in Passage 1 than tryptophane, methionine or IAA. This strong stimulation was also shown ‘indirectly’ after subculture of the roots into arginine medium.The hypothesis is advanced that the growth of excised roots from this strain of groundsel is limited by a suboptimal concentration of some natural auxin‐like substance.