bluuebunny/crossref_metadata_2025 huggingface dataset:
The use of plant wax alkanes as marker substances in studies of the nutrition of herbivores: a review
Authors: Dove H , Mayes RW
Published: November 2004

This review discusses the potential use of plant wax components, especially n-alkanes, as markers for estimating herbage intake, estimating the botanical composition of consumed herbage and studying digesta kinetics. Previous approaches to making these measurements are discussed briefly. Attention is drawn to the fact that current methods for estimating intake do not adequately allow for differences between individual animals. It is also suggested that the markers currently used to estimate botanical composition or study digesta kinetics are inadequate. The nature of the chemical constituents of plant waxes is briefly discussed and the concept of using alkanes to estimate intake is introduced. Particular emphasis is given to the fact that although the recovery of alkanes in faeces is not complete, intake can still be estimated using a pair of alkanes (one natural, one dosed) provided these have similar faecal recoveries. The accuracy of estimation of intake is discussed in terms of: obtaining a representative sample of herbage; alkane dosing and faecal sampling procedures; validity of the assumption of similar recoveries for the natural and dosed alkanes; sample preparation and analysis. Published comparisons of estimated and actual intakes are presented, with the conclusion that satisfactory results are obtained if intake is estimated using natural C33 alkane and dosed C32 alkane. The use of the different patterns of alkanes in herbage species, as a means of estimating botanical composition, is then discussed. Results are presented showing this can be done successfully with herbage mixtures or oesophageal extrusa. Procedures are then described for making the corrections for incomplete faecal alkane recovery, necessary to estimate the botanical composition of the herbage consumed by the free-grazing animal. This allows the quantification of the intake of individual plant species by individual animals, and it is suggested that this can be achieved without the need for oesophageally-fistulated (OF) animals. Differences in alkane levels between plant parts within a species are then discussed. It is suggested that these can lead to error in the estimation of intake, if OF animals should consume plant parts different from those consumed by the test animals. However, it is also suggested that differences in alkane levels between plant parts can be used to quantify the intake of these parts, in a manner analogous to the estimation of the intake of individual plant species. The usefulness of alkanes in studies of digesta kinetics is then discussed, principally in relation to the natural alkanes, which remain intimately associated with plant particles in the gut. It is suggested that natural alkanes could prove excellent markers for studies of particle breakdown and digesta flow. The preparation of natural 14C-labelled alkane, for use as a pulse dose in mean retention time studies, is also discussed.
Effect of supplementary biotin on the reproductive performance, body condition and foot health of sows on three farms
Authors: Greer EB , Leibholz JM , Pickering DI , Macoun RE , Bryden WL
Published: November 2004

A total of 359 sows and 146 gilts on three farms were given either their normal commercial diets or the same diets supplemented with 5008g of biotin/kg of diet over a 15 month period. The diets were based on wheat and meat-and-bone meal. There was no effect of the biotin supplement on the size of litters born or weaned or the number of days between weaning and conception. The body condition of sows during lactation, and in the period from weaning to re-mating, was improved by the biotin supplement. After 12 months, the biotin supplement had reduced the proportion of sows with foot lesions from 55 to 42%.
Agronomic studies on soybean (Glycine max (L.) Merrill) in the dry seasons of the tropics. I. Limits to yield imposed by phenology
Authors: Mayers JD , Lawn RJ , Byth DE
Published: November 2004

An analysis was undertaken of the development, growth and seed yield of irrigated soybean crops grown during the dry season of the semi-arid tropics in north-western Australia, to establish yield potentials and identify major climatic or physiological constraints. Ten tropically adapted genotypes were grown at three sowing times, using agronomic management practices designed to maximize productivity and minimize constraints due to water supply, fertility, weeds and insects. In addition to phenology, seed yield, dry matter (DM) accumulation, and seed and plant morphological traits, measurements were made at the beginning and end of flowering of DM accumulation, leaf area development and interception of photosynthetically active radiation (PAR). Harvest indices were generally large, but maximum seed yields were only c. 3 t ha-1, apparently because of inadequate biomass production. The analysis of growth and development suggested that DM accumulation during the vegetative phase was limited primarily by cumulative PAR interception by the crop canopy rather than the efficiency of conversion of intercepted PAR. In turn, both cumulative PAR interception, and canopy leaf area development, were constrained by precocious flowering, induced by the comparatively short-day/warm temperature conditions of the dry season. It was concluded that yield improvement strategies for the dry season will need to be based on agronomic and/or breeding strategies to enhance canopy development and improve biomass production.
The effect of sowing time, sowing technique and post-sowing weed competition on tall fescue (Festuca arundinacea Schreb.) seedling establishment
Authors: Charles GW , Blair GJ , Andrews AC
Published: November 2004

The effects of sowing time (autumn and spring), sowing technique (conventional cultivation, inverted T direct drill, triple disc direct drill and aerial sowing) and post-sowing weed competition on the establishment of tall fescue were assessed at a field site on the Northern Tablelands of N.S.W. Weed competition [principally Vulpia rnyuros (L.) Gmel.] was removed by pre-sowing herbicide and post-sowing weed control treatments of 0, 30, 60 or 90 days duration. The seedling emergence percentage was monitored until 9 months after the autumn sowing and plots were harvested 9 and 18 months after the autumn sowing. Tall fescue establishment averaged 46 seedlings m-2 from the spring sowing, successful establishment of 15% of viable seed, and 3.5 times better than for the autumn sowing. Eighteen months after sowing, the average dry matter yield of fescue was 960 kg ha-1 for the spring sowing, 33% higher than for the autumn sowing. Aerial sowing resulted in less than 3% establishment at either sowing time. The establishment from the direct drilling machines were equal to that of the cultivated seedbed in the autumn sowing (16 seedlings m-1). In the spring sowing, 79 seedlings m-2 established from the inverted T sowing technique, 43% more than for the cultivated seedbed, and 115% more than for the triple disc. Fourteen months after the spring sowing, post-sowing weed control had reduced the yield of the unsown species 82% on average, and increased the yield of tall fescue by 11956, but had no effect on the final number of established fescue plants. These results show the potential for the establishment of tall fescue on the Northern Tablelands from direct drilling in spring, avoiding many of the problems currently associated with establishment from conventional cultivation in autumn.
Some effects of epidermal growth factor at three stages of pregnancy in Merino ewes
Authors: Hazelton IG , Panaretto BA , Stockwell PR , Marshall JT , Nancarrow CD
Published: November 2004

Pregnant Merino ewes were treated with 90 8g murine epidermal growth factor (EGF) per kg body weight at either 25 (n = 80), 50 (n= 40) or 75 (n =40) days of gestation. Untreated control ewes were included at each gestational age (n=20, 12 and 12 respectively). Fifteen and twenty per cent of the ewes treated with EGF at days 25 and 50 respectively failed to lamb, significantly more (P < 0.01 ) than in ewes treated at day 75, where only one ewe failed to lamb, and in control ewes which all lambed. These differences were not reflected in significant differences between the overall percentage of lambs born in each group, as the incidence of abortion in single-bearing ewes was higher than in ewes carrying multiple fetuses. All lambs born alive to EGF-treated ewes appeared normal. Plasma progesterone concentrations measured before treatment and at 8, 24 and 48 h after EGF injection fell significantly in treated ewes relative to controls (P<0.01 at day 25; P<0.05 at days 50 and 75) and concentrations were lowest at 8 and 24 h after injection in those ewes which aborted. Following EGF treatment at days 25 and 50 of gestation, abortion occurred in all ewes with very low plasma progesterone concentrations 8 to 48 h after EGF injection, probably as a result of EGF-induced luteolysis. In other ewes plasma progesterone concentrations returned to pretreatment values by 48 h, indicating incomplete luteolysis. The delayed abortion observed in some of these ewes further suggests that other mechanisms of action are involved in EGF-induced abortion.
Effect of spraytopping applications of paraquat and glyphosate on the nutritive value and regeneration of vulpia (Vulpia bromoides (L.) S.F. Gray)
Authors: Leys AR , Cullis BR , Plater B
Published: November 2004

The effects of paraquat and glyphosate on the nutritive value of dry residues of vulpia [Vulpia bromoides (L.) S. F. Gray], and its subsequent regeneration the following year were examined at Wagga Wagga during the spring, summer and winter of 1986/87 and 1987/88. Paraquat (100 and 200 g a.i./ha) and glyphosate (135 and 270 g a.i./ha) were applied as spraytopping treatments at heading, anthesis and early grain filling stages of vulpia. For both herbicides, time of application was critical to the level of regeneration obtained. Glyphosate gave 84 and 83% control when applied at heading and anthesis respectively, delaying application until early grain filling reduced the level of vulpia control to 28%. Paraquat gave 81% control when applied at anthesis, while delaying application until early grain filling, or earlier application at heading, gave 59% control. Crude protein (CP) and water-soluble carbohydrate (WSC) concentrations, and in vitro organic matter digestibilities (OMD) were measured in vulpia residues collected for 16 weeks after herbicide application. Paraquat increased CP levels most when applied at heading (from 4-8 to 7.2% in 1986, and from 4.9 to 6.5% in 1987). Glyphosate increased CP levels most when applied at heading in 1986 (from 4.8 to 5.4%), but at anthesis in 1987 (from 4.9 to 6.5%). Glyphosate increased WSC most when applied at heading (from 5.7 to 10.6% in 1986, and from 3.5 to 6.3% in 19871, while paraquat reduced WSC in both years. Application of glyphosate at heading was the only treatment to increase OMD (from 50.5 to 54.7%).
Potential for increasing early vigour and total biomass in spring wheat. II. Characteristics associated with early vigour
Authors: Regan KL , Siddique KHM , Turner NC , Whan BR
Published: November 2004

Increased early growth and total dry matter production have been suggested as useful traits to improve yield in Mediterranean-type environments. In Part I, genotypic variation for early growth and total dry matter production was identified among cultivars and some introduced lines. In this part, characteristics associated with early vigour in five of these introduced lines and ten Australian cultivars were examined in a field study at Wongan Hills in Western Australia. Differences in dry matter production were observed at all sampling times during the season, with three of the introduced lines (CEP 8058, Kansu No. 32 and V979-28) having consistently higher dry matter production than the standard cultivars during the early growth period. Those genotypes with a higher dry matter production at 54 days after sowing had higher relative growth rates and green area indices than those with low dry matter production. Both genotypes with large leaves on few tillers and genotypes with small leaves on many tillers had higher green area indices and higher dry matter production. While high dry matter production was associated with a large degree of ground cover and high light interception, it was not associated with the earlier commencement of reproductive development. Incorporation of early vigour and high dry matter production into locally adapted cultivars is required to demonstrate its benefit in these environments.
Water stress affects the productivity, growth components, competitiveness and water relations of phalaris and white clover growing in a mixed pasture
Authors: Guobin L , Kemp DR , Liu GB
Published: November 2004

The effect of water stress during summer and recovery after rain on herbage accumulation, leaf growth components, stomatal conductance and leaf water relations of white clover (Trifolium repens cv. Haifa) and phalaris (Phalaris aquatica cv. Australian Commercial) was studied in an established mixed pasture under dryland (dry) or irrigated (wet) conditions. Soil water deficits under dry conditions reached 150 mm and soil water potentials in the top 20 cm declined to nearly -2 MPa after 50 days of dry weather. Water stress severely restricted growth of both species but then after rain fell, white clover growth rates exceeded those of phalaris. Under irrigation, white clover produced twice the herbage mass of phalaris but under dry conditions herbage production was similar from both species. Leaf appearance rates per tiller or stolon were slightly higher for white clover than phalaris but were reduced by 20% under water stress in both species. Leaf or petiole extension rates were more sensitive to water stress than leaf appearance rates and declined by 75% in phalaris and 90% in white clover. The ratio of leaf or petiole extension rates on dry/wet treatments was similar for both species in relation to leaf relative water contents, but in relation to leaf water potentials phalaris maintained higher leaf growth rates. Phalaris maintained a higher leaf relative water content in relation to leaf water potentials than did white clover and also maintained higher leaf water potentials in relation to the soil water potential in the top 20 cm. Stomata1 conductances for both species declined by 80-90% with increasing water stress, and both species showed similar stomatal responses to bulk leaf water potentials and leaf relative water contents. It is suggested that the poorer performance of white clover under water stress may be due principally to a shallower root system than phalaris and not due to any underlying major physiological differences. The white clover cultivar used in this study came from the mediterranean region and showed some different responses to water stress than previously published evidence on white clover. This suggests genetic variation in responses to water stress may exist within white clover. To maintain white clover in a pasture under dry conditions it is suggested that grazing practices aim to retain a high proportion of growing points.
Partitioning of dry matter into primary branches and pod initiation on the main inflorescence of Lupinus angustifolius
Authors: Pigeaire A , Seymour M , Delane R , Atkins CA
Published: November 2004

The hypothesis that pod load on the main inflorescence of Lupins angustifolius (L.) is negatively coupled to the amount of dry matter partitioned into primary branches was tested. Growth rates of main stem and primary branches during the period of pod initiation were measured in a series of field experiments at two different sites. Variation in pod set was generated experimentally by varying sowing date or density and by using four cultivars (Yandee, Danja, Gungurru and Warrah). The cultivars differed in their total growth rate, but not in the way dry matter was partitioned into main stem and primary branches. In contrast, significant variation in dry matter partitioning was observed for cv. Danja tested across site and sowing date. With increased plant density, at the same sowing date, the proportion of dry matter allocated to branches increased consistently, even though it decreased in absolute terms, and the number of pods initiated on the main infloresence also decreased consistently. Thus a negative relationship between pod load and the proportion of dry matter allocated into branches was observed as a result of variation in density. However, there was no consistent relationship when variations in pod load were induced by site, date of sowing or cultivar. These data are interpreted to indicate that increased pod initiation on the main inflorescence is not necessarily coupled with decreased partitioning of dry matter into primary branches.
Transplanted human bone marrow contributes to vascular endothelium
Authors: Jiang Shuguang , Walker Luke , Afentoulis Michael , Anderson Daniel A. , Jauron-Mills Linda , Corless Christopher L. , Fleming William H.
Published: November 2004

Recent evidence indicates that bone marrow is a source of endothelial progenitor cells that are mobilized into the peripheral blood in response to cytokines or tissue injury. Previously, we showed that functional endothelial cells (ECs) can be clonally derived from phenotypically defined hematopoietic stem cells. To determine the EC potential of human bone marrow and peripheral blood stem cells, blood vessels in sex-mismatched transplant recipients were evaluated. EC outcomes were identified by using a combination of immunohistochemistry and XY interphase FISH. Donor-derived ECs were detected in the skin and gut of transplant recipients with a mean frequency of 2% and could readily be distinguished from CD45-expressing hematopoietic stem cells. None of the >4,000 ECs examined had more than two sex chromosomes, consistent with an absence of cell fusion. Y chromosome signals were not detected in sex-matched female recipients, excluding the vertical transmission of male cells. None of the recipients evaluated before hematopoietic engraftment demonstrated donor-derived ECs, indicating a close linkage between the recovery of hematopoiesis and EC outcomes. Transplantable bone marrow-derived endothelial progenitor cells may represent novel therapeutic targets for hematopoietic and vascular disease.
Compound library development guided by protein structure similarity clustering and natural product structure
Authors: Koch Marcus A. , Wittenberg Lars-Oliver , Basu Sudipta , Jeyaraj Duraiswamy A. , Gourzoulidou Eleni , Reinecke Kerstin , Odermatt Alex , Waldmann Herbert
Published: November 2004

To identify biologically relevant and drug-like protein ligands for medicinal chemistry and chemical biology research the grouping of proteins according to evolutionary relationships and conservation of molecular recognition is an established method. We propose to employ structure similarity clustering of the ligand-sensing cores of protein domains (PSSC) in conjunction with natural product guided compound library development as a synergistic approach for the identification of biologically prevalidated ligands with high fidelity. This is supported by the concepts that (
i
) in nature spatial structure is more conserved than amino acid sequence, (
ii
) the number of fold types characteristic for all protein domains is limited, and (
iii
) the underlying frameworks of natural product classes with multiple biological activities provide evolutionarily selected starting points in structural space. On the basis of domain core similarity considerations and irrespective of sequence similarity, Cdc25A phosphatase, acetylcholinesterase, and 11β-hydroxysteroid dehydrogenases type 1 and type 2 were grouped into a similarity cluster. A 147-member compound collection derived from the naturally occurring Cdc25A inhibitor dysidiolide yielded potent and selective inhibitors of the other members of the similarity cluster with a hit rate of 2–3%. Protein structure similarity clustering may provide an experimental opportunity to identify supersites in proteins.
Evidence that translocation of anthrax toxin's lethal factor is initiated by entry of its N terminus into the protective antigen channel
Authors: Zhang Sen , Finkelstein Alan , Collier R. John
Published: November 2004

Entry of the enzymatic components of anthrax toxin [lethal factor (LF) and edema factor] into the cytosol of mammalian cells depends on the ability of the activated protective antigen (PA
63
) component to form a channel (pore) in the membrane of an acidic intracellular compartment. To investigate the mechanism of translocation, we characterized N-terminally truncated forms of the PA
63
-binding domain of LF (LF
N
). Deleting 27 or 36 residues strongly inhibited acid-triggered translocation of LF
N
across the plasma membrane of CHO-K1 cells and ablated the protein's ability to block PA
63
channels in planar lipid bilayers at a small positive voltage (+20 mV). Fusing a H
6
-tag to the N terminus of the truncated proteins restored both translocation and channel-blocking activities. At +20 mV, N-terminal H
6
and biotin tags were accessible to Ni
2+
and streptavidin, respectively, added to the trans compartment of a planar bilayer. On the basis of these findings, we propose that the N terminus of PA
63
-bound LF or edema factor enters the PA
63
-channel under the influence of acidic pH and a positive transmembrane potential and initiates translocation in an N- to C-terminal direction.
The structure of carbonmonoxy neuroglobin reveals a heme-sliding mechanism for control of ligand affinity
Authors: Vallone Beatrice , Nienhaus Karin , Matthes Annemarie , Brunori Maurizio , Nienhaus G. Ulrich
Published: November 2004

Neuroglobin (Ngb), a globular heme protein expressed in the brain of vertebrates, binds oxygen reversibly, with an affinity comparable to myoglobin (Mb). Despite low sequence identity, the overall 3D fold of Ngb and Mb is very similar. Unlike in Mb, in Ngb the sixth coordination position of the heme iron is occupied by the distal histidine, in the absence of an exogenous ligand. Endogenous ligation has been proposed as a unique mechanism for affinity regulation and ligand discrimination in heme proteins. This peculiarity might be related to the still-unknown physiological function of Ngb. Here, we present the x-ray structure of CO-bound ferrous murine Ngb at 1.7 Å and a comparison with the 1.5-Å structure of ferric bis-histidine Ngb. We have also used Fourier transform IR spectroscopy of WT and mutant CO-ligated Ngb to examine structural heterogeneity in the active site. Upon CO binding, the distal histidine retains (by and large) its position, whereas the heme group slides deeper into a preformed crevice, thereby reshaping the large cavity (≈290 Å
3
) connecting the distal and proximal heme sides with the bulk. The heme relocation is accompanied by a significant decrease of structural disorder, especially of the EF loop, which may be the signal whereby Ngb communicates hypoxic conditions. This unexpected structural change unveils a heme-sliding mechanism of affinity control that may be of significance to understanding Ngb's role in the pathophysiology of the brain.
Analysis of Mutant Phenotypes and Splicing Defects Demonstrates Functional Collaboration between the Large and Small Subunits of the Essential Splicing Factor U2AF In Vivo
Authors: Webb Christopher J. , Lakhe-Reddy Sujata , Romfo Charles M. , Wise Jo Ann
Published: November 2004

The heterodimeric splicing factor U2AF plays an important role in 3′ splice site selection, but the division of labor between the two subunits in vivo remains unclear. In vitro assays led to the proposal that the human large subunit recognizes 3′ splice sites with extensive polypyrimidine tracts independently of the small subunit. We report in vivo analysis demonstrating that all five domains of spU2AFLGare essential for viability; a partial deletion of the linker region, which forms the small subunit interface, produces a severe growth defect and an aberrant morphology. A small subunit zinc-binding domain mutant confers a similar phenotype, suggesting that the heterodimer functions as a unit during splicing in Schizosaccharomyces pombe. As this is not predicted by the model for metazoan 3′ splice site recognition, we sought introns for which the spU2AFLGand spU2AFSMmake distinct contributions by analyzing diverse splicing events in strains harboring mutations in each partner. Requirements for the two subunits are generally parallel and, moreover, do not correlate with the length or strength of the 3′ pyrimidine tract. These and other studies performed in fission yeast support a model for 3′ splice site recognition in which the two subunits of U2AF functionally collaborate in vivo.
The Role of Microtubules in Rapid Hyphal Tip Growth ofAspergillus nidulans
Authors: Horio Tetsuya , Oakley Berl R.
Published: November 2004

The filamentous fungus Aspergillus nidulans grows by polarized extension of hyphal tips. The actin cytoskeleton is essential for polarized growth, but the role of microtubules has been controversial. To define the role of microtubules in tip growth, we used time-lapse microscopy to measure tip growth rates in germlings of A. nidulans and in multinucleate hyphal tip cells, and we used a green fluorescent protein-α-tubulin fusion to observe the effects of the antimicrotubule agent benomyl. Hyphal tip cells grew ≈5 times faster than binucleate germlings. In germlings, cytoplasmic microtubules disassembled completely in mitosis. In hyphal tip cells, however, microtubules disassembled through most of the cytoplasm in mitosis but persisted in a region near the hyphal tip. The growth rate of hyphal tip cells did not change significantly in mitosis. Benomyl caused rapid disassembly of microtubules in tip cells and a 10× reduction in growth rate. When benomyl was washed out, microtubules assembled quickly and rapid tip growth resumed. These results demonstrate that although microtubules are not strictly required for polarized growth, they are rate-limiting for the growth of hyphal tip cells. These data also reveal that A. nidulans exhibits a remarkable spatial regulation of microtubule disassembly within hyphal tip cells.
Slipping or Gripping? Fluorescent Speckle Microscopy in Fish Keratocytes Reveals Two Different Mechanisms for Generating a Retrograde Flow of Actin
Authors: Jurado Carlos , Haserick John R. , Lee Juliet
Published: November 2004

Fish keratocytes can generate rearward directed traction forces within front portions of the lamellipodium, suggesting that a retrograde flow of actin may also occur here but this was not detected by previous photoactivation experiments. To investigate the relationship between retrograde flow and traction force generation, we have transfected keratocytes with GFP-actin and used fluorescent speckle microscopy, to observe speckle flow. We detected a retrograde flow of actin within the leading lamellipodium that is inversely proportional to both protrusion rate and cell speed. To observe the effect of reducing contractility, we treated transfected cells with ML7, a potent inhibitor of myosin II. Surprisingly, ML7 treatment led to an increase in retrograde flow rate, together with a decrease in protrusion and cell speed, but only in rapidly moving cells. In slower moving cells, retrograde flow decreased, whereas protrusion rate and cell speed increased. These results suggest that there are two mechanisms for producing retrograde flow. One involves slippage between the cytoskeleton and adhesions, that decreases traction force production. The other involves slippage between adhesions and the substratum, which increases traction force production. We conclude that a biphasic relationship exists between retrograde actin flow and adhesiveness in moving keratocytes.
Capital markets and capital allocation: Implications for economies in transition*
Authors: Durnev Art , Li Kan , Mørck Randall , Yeung Bernard
Published: November 2004

Recent work showing that a sounder financial system is associated with faster economic growth has important implications for transition economies. Stock prices in developed economies move in highly firm‐specific ways that convey information about changes in firms’ marginal value of investment. This information facilitates the rapid flow of capital to its highest value uses. In contrast, stock prices in low‐income countries tend to move up and down en masse, and thus are of scant use for microeconomic capital allocation. Some transition economy markets are coming to resemble those of developed economies, others those of low‐income countries. Stock return asynchronicity is highly correlated with the strength of private property rights in general and public shareholders’ rights in particular. Other recent work suggests that small entrenched elites in low‐income countries preserve their sweeping control over the corporate sectors of their economies by using political influence to undermine the financial system and deprive entrants of capital. The lack of cross‐sectional independence in some transition economies’ stock returns may be a warning of such economic entrenchment. Sound property rights, solid shareholder rights, stock market transparency, and capital account openness appear to check this, and thus contribute to efficient capital allocation and economic growth.
The prognostic value of pre‐operative predicted forced vital capacity in corrective spinal surgery for Duchenne's muscular dystrophy
Authors: Harper C. M. , Ambler G. , Edge G.
Published: November 2004

The majority of patients with Duchenne's muscular dystrophy require corrective spinal surgery for scoliosis to maintain seated balance and to slow the progression of respiratory compromise, thereby facilitating nursing and enhancing their quality of life. Traditionally patients with a pre‐operative forced vital capacity (PFVC) of 30% or below predicted have been denied this surgery as it was thought that the incidence of postoperative complications was unacceptably high. We present data collected prospectively from 45 consecutive operations undertaken in our unit. These cases indicate that there is no clinically significant difference in operative and postoperative outcomes between patients with PFVC > 30% and ≤30%. However, the routine postoperative use of mask ventilation to facilitate early tracheal extubation is vital.
Chemokine receptor expression in the human ectocervix: implications for infection by the human immunodeficiency virus‐type I
Authors: Yeaman Grant R. , Asin Susana , Weldon Sally , Demian Douglas J. , Collins Jane E. , Gonzalez Jorge L. , Wira Charles R. , Fanger Michael W. , Howell Alexandra L.
Published: November 2004

Human immunodeficiency virus‐type 1 (HIV‐1) is a sexually transmitted pathogen that can infect cells in the female reproductive tract (FRT). The mechanism of viral transmission within the FRT and the mode of viral spread to the periphery are not well understood. To characterize the frequency of potential targets of HIV infection within the FRT, we performed a systematic study of the expression of HIV receptors (CD4, galactosyl ceramide (GalCer)) and coreceptors (CXCR4 and CCR5) on epithelial cells and leucocytes from the ectocervix. The ectocervix is a likely first site of contact with HIV‐1 following heterosexual transmission, and expression of these receptors is likely to correlate with susceptibility to viral infection. We obtained ectocervical tissue specimens from women undergoing hysterectomy, and compared expression of these receptors among patients who were classified as being in the proliferative or secretory phases of their menstrual cycle at the time of hysterectomy, as well as from postmenopausal tissues. Epithelial cells from tissues at early and mid‐proliferative stages of the menstrual cycle express CD4, although by late proliferative and secretory phases, CD4 expression was absent or weak. In contrast, GalCer expression was uniform in all stages of the menstrual cycle. CXCR4 expression was not detected on ectocervical epithelial cells and positive staining was only evident on individual leucocytes. In contrast, CCR5 expression was detected on ectocervical epithelial cells from tissues at all stages of the menstrual cycle. Overall, our results suggest that HIV infection of cells in the ectocervix could most likely occur through GalCer and CCR5. These findings are important to define potential targets of HIV‐1 infection within the FRT, and for the future design of approaches to reduce the susceptibility of women to infection by HIV‐1.
T cell receptor induced intracellular redistribution of type I protein kinase A
Authors: Zhou Wenhong , Vergara Leoncio , König Rolf
Published: November 2004

The productive activation of CD4+ T lymphocytes, leading to proliferation and cytokine secretion, requires precise temporal regulation of intracellular cyclic AMP concentrations. The major effector molecule activated by cyclic AMP in mammalian cells is the cyclic AMP‐dependent protein kinase A (PKA). The type I PKA isozyme mediates the inhibitory effects of cyclic AMP on T‐cell activation. Using laser scanning confocal microscopy, we demonstrated that the regulation of PKA type I activity involves spatial redistribution of PKA type I molecules following T‐cell receptor (TCR) stimulation. In resting T cells, PKA type I was located in membrane proximal regions and distributed equally across the cell. Shortly after antigen engagement, T cells and antigen‐presenting cells formed an area of intense contact, known as the immunological synapse. TCR concentrated at the synapse, whereas PKA type I molecules redistributed to the opposite cell pole within 10 min after T‐cell stimulation. Type I PKA redistribution was solely dependent on TCR signalling, because we observed the same temporal and spatial distribution after antibody‐mediated cross‐linking of the TCR‐associated CD3 complex. Segregation of TCR and PKA type I molecules was maintained for at least 20 min. Thirty minutes after stimulation, PKA type I partially colocalized with the TCR. After 60 min, PKA type I distribution again approached the resting state. Considering that initial TCR signals lead to increases in intracellular cyclic AMP, PKA type I molecules may be targeted towards localized cyclic AMP accumulations or transported away from these areas, depending on the requirements of the cellular response.
Regulation of T‐cell receptor signalling by membrane microdomains
Authors: Razzaq Tahir M. , Ozegbe Patricia , Jury Elizabeth C. , Sembi Phupinder , Blackwell Nathan M. , Kabouridis Panagiotis S.
Published: November 2004

There is now considerable evidence suggesting that the plasma membrane of mammalian cells is compartmentalized by functional lipid raft microdomains. These structures are assemblies of specialized lipids and proteins and have been implicated in diverse biological functions. Analysis of their protein content using proteomics and other methods revealed enrichment of signalling proteins, suggesting a role for these domains in intracellular signalling. In T lymphocytes, structure/function experiments and complementary pharmacological studies have shown that raft microdomains control the localization and function of proteins which are components of signalling pathways regulated by the T‐cell antigen receptor (TCR). Based on these studies, a model for TCR phosphorylation in lipid rafts is presented. However, despite substantial progress in the field, critical questions remain. For example, it is unclear if membrane rafts represent a homogeneous population and if their structure is modified upon TCR stimulation. In the future, proteomics and the parallel development of complementary analytical methods will undoubtedly contribute in further delineating the role of lipid rafts in signal transduction mechanisms.
Structural modifications in Rhizobium meliloti Nod factors influence their stability against hydrolysis by root chitinases
Authors: Staehelin Christian , Schultze Michael , Kondorosi Éva , Mellor Robert B. , Boiler Thomas , Kondorosi Adam
Published: November 2004

Acylated chitooligosaccharide signals (Nod factors) trigger the development of root nodules on leguminous plants and play an important role in determining host specificity in the Rhizobium‐plant symbiosis. Here, the ability of plant chitinases to hydrolyze different Nod factors and the potential significance of the structural modifications of Nod factors in stabilizing them against enzymatic inactivation were investigated. Incubation of the sulfated Nod factors of Rhizobium meliloti, NodRm‐IV(S) and NodRm‐V(S), as well as their desulfated derivatives NodRm‐IV and NodRm‐V, with purified chitinases from the roots of the host plant Medicago and the nonhost plant Vicia resulted in the release of the acylated lipotrisaccharide NodRm‐III from NodRm‐V, NodRm‐IV and NodRm‐V(S), whereas NodRm‐IV(S) was completely resistant to digestion by both chitinases. Kinetic analysis showed that the structural parameters determining host specificity, the length of the oligosaccharide chain, the acylation at the nonreducing end and the sulfatation at the reducing end of the lipooligosaccharide, influence the stability of the molecule against degradation by chitinases. When the Nod factors were incubated in the presence of intact roots of Medicago, as well as of Vicia, the acylated lipotrisaccharide was similarly released in vivo from all Nod factors except NodRm‐IV(S). In addition, a dimer‐forming activity was observed in intact roots which also cleaved NodRm‐IV(S). This activity was much greater in Medicago than in Vicia and increased upon incubation. The initial overall degradation rate of the Nod factors on Medicago was inversely correlated with their biological activities on Medicago roots. These results open the possibility that the activity of Nod factors on Medicago may partly be determined by the action of chitinases.
Gibberellic acid‐induced microtubule reorientation in dwarf peas is accompanied by rapid modification of an α‐tubulin isotype
Authors: Duckett Catherine M. , Lloyd Clive W.
Published: November 2004

To test whether shifts induced in microtubuie orientation by gibberellic acid (GA3) involved changes in tubulin isotypes, pea stem cells were examined when elongation had been enhanced by GA3. The behaviour of a dwarf recessive mutation (le), with very low endogenous levels of gibberellin, was compared with the tall (Le) plant.

Two hours after adding GA3, cells were measurably longer than controls and this coincided with a net shift of microtubule orientation from longitudinal and oblique to transverse — an effect that was more pronounced in the dwarf. There were always more cells with net‐transverse microtubules in GA3‐treated tissue than in controls, but as growth ceased, the major orientation of the microtubule arrays became oblique in both samples. Microtubule reorientation was rapid and was closely correlated with the growth of the cells.

Although changes in orientation and isotype were monitored over a 40 h period, immunoblotting 2D gels with the well characterized antibodies YL1/2 and YOL1/34 confirmed that alterations to the α‐tubulin constellation could be detected as early as the 2 h time point. Again the effect was especially pronounced in dwarf plants. In the presence of added GA3, one α‐tubulin isotype (designated α1) retained its position in the α‐tubulin constellation (as determined by total protein staining and with YOL1/34 that recognizes detyrosinated as well as tyrosinated tubulin). It was no longer recognized, however, by the anti‐tyrosinated α‐tubulin antibody YL1/2.

This indicates that as GA3 begins to cause a reorientation of the cortical microtubules (and to enhance the rate of cell elongation) the α1 isotype is rapidly changed, probably by post‐translational modification.
Regulation of pea cytosolic ascorbate peroxidase and other antioxidant enzymes during the progression of drought stress and following recovery from drought
Authors: Mittler Ron , Zilinskas Barbara A.
Published: November 2004

The molecular mechanism underlying the regulation of the expression of Apxl, the gene encoding cytosolic ascorbate peroxidase, as well as other antioxidant enzymes, was studied during the progression of drought stress and following recovery from drought. Increase in steady‐state transcript levels of the cytosolic isozymes of ascorbate peroxidase and Cu/Zn‐superoxide dismutase paralleled the increase in stomatal resistance during drought stress, but was even more dramatically enhanced following recovery from drought. Cytosolic Cu/Zn‐superoxide dismutase and ascorbate peroxidase and chloroplastic Cu/Zn‐superoxide dismutase protein and activity increased during drought stress and following recovery. In contrast, catalase activity increased during drought stress but returned to normal levels following recovery. During recovery from drought stress, cytosolic ascorbate peroxidase expression was regulated post‐transcriptionally at the level of protein synthesis. The transcription rate of the Apxl gene, as determined by nuclear run‐on assay, increased during drought stress and at 10 h following rewatering.
Recovery of transgenic peanut (Arachis hypogaea L.) plants from elite cultivars utilizing ACCELL® technology
Authors: Brar Gurdip S. , Cohen Barry A. , Vick Carole L. , Johnson Grant W.
Published: November 2004

Transgenic plants of Florunner and Florigiant, two of the most widely cultivated peanut cultivars in the USA, have been developed using the ACCELL® gene delivery method. Shoot meristems of mature embryonic axes were bombarded with gold beads coated with DNA encoding β‐glucuronidase (gus), phosphinothricin acetyl transferase (bar), and tomato spotted wilt virus‐nucleocapsid protein (tswv‐np) genes. Transgenic shoots were identified by screening for GUS activity, and independent transformants were recovered from both cultivars. Molecular analysis of two of these transformants in R0 and R1 generations demonstrated the stable integration of the foreign genes into the plant genome. One transgenic plant had one to two copies of the genes integrated into the genome of its progeny, whereas the other had multiple copies. Gus and bar genes exhibited predictable segregation ratios in the R1 and R2 generations and were genetically linked. Integration of the bar gene conferred resistance to BASTATM, a wide‐spectrum herbicide, applied at 500 p.p.m. of active ingredient. Resistance of the transgenic plants to tomato spotted wilt virus is currently being tested under greenhouse conditions. The ACCELL® particle bombardment system is expected to be effective for transformation of a wide variety of commercial peanut cultivars.
Initiation and propagation behaviour of fatigue cracks in hard‐shot peened Type 316L steel in high cycle fatigue
Authors: MASAKI K. , OCHI Y. , MATSUMURA T.
Published: November 2004

Observations of fatigue crack growth behaviour were made during rotating‐bend testing of hard‐shot peened Type 316L steel. From the results of these observations, the crack that developed in the axial direction was observed and the mechanism of the fatigue crack properties was clarified as follows: (1) Small circumferential surface fatigue cracks were detected at 60% of the fatigue lifetime. These cracks propagated very slowly in both the circumferential and radial directions. (2) When a radial crack reached a depth of between 150 and 350 μm, axial fatigue cracks were formed. (3) In the next stage, either the radial or the axial fatigue cracks continued propagating, or an inwards growing radial crack formed from the axial crack. (4) In the final stage, the circumferential surface crack began to grow rapidly and resulted in fracture. (5) The fracture type of hard‐shot peened Type 316L is a particular type of surface fracture.
Fatigue life prediction under wide band random loading
Authors: PETRUCCI G. , ZUCCARELLO B.
Published: November 2004

In this paper, a method for the high‐cycle fatigue life prediction of components subjected to gaussian, stationary, wide band random loading is presented. It allows the user to evaluate the fatigue life of components subjected to uniaxial stress states directly from the stress power spectral density (PSD), avoiding onerous simulations in time domain. The proposed method can be applied to random stress processes having PSD of any shape, and the fatigue life predictions obtained are more accurate than that provided by most of the frequency domain techniques proposed in literature.
The effect of a school‐wide inclusion training programme upon teachers’ attitudes about inclusion
Authors: Wilkins Tina , Nietfeld John L.
Published: November 2004

This study compared survey responses of teachers from a reform‐based programme focused on promoting inclusion‐based classrooms, namely Project WINS (Winning Ideas Network for Schools) schools, with teachers from non‐Project WINS schools with regard to their attitude about inclusion in the classroom. Surprisingly, the results of this study revealed no differences between the two groups of teachers on most facets of inclusion. The one significant difference found a greater preference for inclusion by non‐Project WINS teachers with regard to classroom climate. The study also revealed a higher preference for inclusion for teachers with higher self‐reported expertise in special education regardless of what group the teacher was surveyed from. Findings from this study indicate the need for further research and improvements in training methods for Project WINS and similar programmes that attempt to change teachers’ attitudes towards inclusion as an important first step in improving practice in inclusion‐based classrooms.

As the movement for more inclusion in schools increases, administrators, special educators and teachers are caught in the midst of the tide. Proponents of inclusion believe change is needed now, but those not in favour of such changes recommend not implementing inclusion without further research (Snyder, 1999). In addition, schools need assistance in developing and implementing policies and practices that will lead to an effective inclusion experience for all parties involved (Johnson, 2000). The primary purpose of this study was to further this research by examining attitudes related to inclusion of teachers participating in a programme implemented in middle schools with the explicit goal of fostering effective inclusion‐based classrooms. Second, we tested the relationship between perceived expertise in special education and attitudes towards inclusion. Below we briefly describe some of the factors that research has shown to influence teachers’ level of acceptance of inclusion‐based classrooms.
Half‐lives of docosahexaenoic acid in rat brain phospholipids are prolonged by 15 weeks of nutritional deprivation of n‐3 polyunsaturated fatty acids
Authors: DeMar James C. , Ma Kaizong , Bell Jane M. , Rapoport Stanley I.
Published: November 2004

Male rat pups (21 days old) were placed on a diet deficient in n‐3 polyunsaturated fatty acids (PUFAs) or on an n‐3 PUFA adequate diet containing α‐linolenic acid (α‐LNA; 18 : 3n‐3). After 15 weeks on a diet, [4,5‐3H]docosahexaenoic acid (DHA; 22 : 6n‐3) was injected into the right lateral cerebral ventricle, and the rats were killed at fixed times over a period of 60 days. Compared with the adequate diet, 15 weeks of n‐3 PUFA deprivation reduced plasma DHA by 89% and brain DHA by 37%; these DHA concentrations did not change thereafter. In the n‐3 PUFA adequate rats, DHA loss half‐lives, calculated by plotting log10 (DHA radioactivity) against time after tracer injection, equaled 33 days in total brain phospholipid, 23 days in phosphatidylcholine, 32 days in phosphatidylethanolamine, 24 days in phosphatidylinositol and 58 days in phosphatidylserine; all had a decay slope significantly greater than 0 (p < 0.05). In the n‐3 PUFA deprived rats, these half‐lives were prolonged twofold or greater, and calculated rates of DHA loss from brain, Jout, were reduced. Mechanisms must exist in the adult rat brain to minimize DHA metabolic loss, and to do so even more effectively in the face of reduced n‐3 PUFA availability for only 15 weeks.